U.S. patent application number 12/812304 was filed with the patent office on 2010-11-11 for compositions and methods for adoptive and active immunotherapy.
This patent application is currently assigned to Yale University. Invention is credited to Tarek Fahmy, Erin Steenblock.
Application Number | 20100284965 12/812304 |
Document ID | / |
Family ID | 40901597 |
Filed Date | 2010-11-11 |
United States Patent
Application |
20100284965 |
Kind Code |
A1 |
Fahmy; Tarek ; et
al. |
November 11, 2010 |
COMPOSITIONS AND METHODS FOR ADOPTIVE AND ACTIVE IMMUNOTHERAPY
Abstract
Modular aAPCs and methods of their manufacture and use are
provided. The modular aAPCs are constructed from polymeric
microparticles. The aAPCs include encapsulated cytokines and
coupling agents which modularly couple functional elements
including T cell receptor activators, co-stimulatory molecules and
adhesion molecules to the particle. The ability of these aAPCs to
release cytokines in a controlled manner, coupled with their
modular nature and ease of ligand attachment, results in an ideal,
tunable APC capable of stimulating and expanding primary T
cells.
Inventors: |
Fahmy; Tarek; (New Haven,
CT) ; Steenblock; Erin; (Janesville, WI) |
Correspondence
Address: |
Pabst Patent Group LLP
1545 PEACHTREE STREET NE, SUITE 320
ATLANTA
GA
30309
US
|
Assignee: |
Yale University
|
Family ID: |
40901597 |
Appl. No.: |
12/812304 |
Filed: |
January 14, 2009 |
PCT Filed: |
January 14, 2009 |
PCT NO: |
PCT/US09/30966 |
371 Date: |
July 9, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61021258 |
Jan 15, 2008 |
|
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|
Current U.S.
Class: |
424/85.2 ;
424/85.1; 424/85.5; 424/85.6; 424/85.7; 424/93.71; 977/773;
977/906 |
Current CPC
Class: |
A61P 37/06 20180101;
A61K 39/39 20130101; C12N 2501/23 20130101; A61K 2039/55533
20130101; C12N 5/0636 20130101; A61K 2039/55555 20130101; A61K
47/6425 20170801; A61K 47/646 20170801; A61K 2039/55516 20130101;
A61P 37/08 20180101; A61P 37/00 20180101; A61K 47/6935 20170801;
C12N 2531/00 20130101; A61K 47/6925 20170801; A61K 9/1647 20130101;
A61P 35/00 20180101; C12N 2501/51 20130101; C12N 2501/515 20130101;
A61K 2039/5158 20130101; C12N 2533/40 20130101 |
Class at
Publication: |
424/85.2 ;
424/85.1; 424/85.7; 424/85.6; 424/85.5; 424/93.71; 977/773;
977/906 |
International
Class: |
A61K 35/12 20060101
A61K035/12; A61K 38/19 20060101 A61K038/19; A61K 38/20 20060101
A61K038/20; A61K 38/21 20060101 A61K038/21; A61P 35/00 20060101
A61P035/00; A61P 37/06 20060101 A61P037/06; A61P 37/00 20060101
A61P037/00; A61P 37/08 20060101 A61P037/08 |
Goverment Interests
GOVERNMENT SUPPORT
[0002] This invention was made with government support under an
appointment to the Department of Homeland Security (DHS)
Scholarship and Fellowship Program, administered by the Oak Ridge
Institute for Science and Education (ORISE) through an interagency
agreement between the U.S. Department of Energy (DOE) and DHS.
ORISE is managed by Oak Ridge Associated Universities (ORAU) under
DOE contract number DE-AC05-06OR23100. The government has certain
rights in the invention.
Claims
1-18. (canceled)
19. A method for modulating an immune response comprising
administering to an individual in need thereof or cells for
administration to the individual polymeric nano or microparticles
having at least one cytokine encapsulated in or incorporated onto
or into the nano- or microparticles to effect paracrine release of
the cytokine.
20. The method of claim 19 wherein the nano or microparticles
comprise coupling agents bound to or incorporated into the surface
of the nano- or microparticles, at least one T cell receptor
activator bound to the nano- or microparticles or at least one
co-stimulatory molecule bound to the nano- or microparticles.
21. The method of claim 20, wherein the T cell receptor activators
and/or the co-stimulatory molecules are bound to the nano- or
microparticles by the coupling agents.
22. The method of claim 20, wherein the coupling agents are
conjugated to affinity tags.
23. The method of claim 22, wherein the coupling agents are bound
to the T cell receptor activators and the co-stimulatory molecules
by the non-covalent interaction of the affinity tag conjugated to
the coupling agents and complementary affinity tags conjugated to
the T cell receptor activators and the co-stimulatory
molecules.
24. The method of claim 19, wherein the at least one cytokine is
selected from the group consisting of granulocyte macrophage colony
stimulating factor (GM-CSF), tumor necrosis factor alpha
(TNF.alpha.), tumor necrosis factor beta (TNF.beta.), macrophage
colony stimulating factor (M-CSF), interleukin-1 (IL-1),
interleukin-2 (IL-2), interleukin-4 (IL-4), interleukin-5 (IL-5),
interleukin-6 (IL-6), interleukin-10 (IL-10), interleukin-12
(IL-12), interleukin-15 (IL-15), interleukin-21 (IL-21), interferon
alpha (IFN.alpha.), interferon beta (IFN.beta.), interferon gamma
(IFN.gamma.), and IGIF, and variants and fragments thereof.
25. The method of claim 20, wherein the at least one T cell
receptor activator is a polyclonal T cell receptor activator.
26. The method of claim 20, wherein the at least one T cell
receptor activator comprises MHC molecules bound to peptide
antigens.
27. The method of claim 20, comprising at least one co-stimulatory
molecule is selected from the group consisting of CD7, B7-1 (CD80),
B7-2 (CD86), PD-L1, PD-L2, 4-1BBL, OX40L, inducible co-stimulatory
ligand (ICOS-L), intercellular adhesion molecule (ICAM), CD2, CD5,
CD9, CD30L, CD40, CD70, CD83, HLA-G, MICA, MICB, HVEM, lymphotoxin
beta receptor, 3/TR6, ILT3, ILT4, HVEM, a ligand that specifically
binds with B7-H3, a ligand that specifically binds with CD83 and
antibodies that specifically bind with Toll ligand receptor, CD27,
CD28, 4-1BB, OX40, CD30, CD40, PD-1, ICOS, lymphocyte
function-associated antigen-1 (LFA-1), CD2, CD7, LIGHT, NKG2C and
B7-H3 and variants and fragments thereof.
28. A method for adoptive immunotherapy of a disease or disorder in
an individual to be treated comprising isolating a population of T
cells from a subject to be treated, activating the T cells by
administering to the cells polymeric nano or microparticles having
at least one cytokine encapsulated in or incorporated onto or into
the nano- or microparticles to effect paracrine release of the
cytokine, expanding the T cells, and administering the T cells to
the subject to be treated in an amount effective to induce an
immune response.
29. The method of claim 28, wherein the aAPCs preferentially expand
CD8.sup.+ T cells as compared to CD4+ T cells.
30. The method of claim 19, wherein the individual to be treated
has a disease or disorder selected from the group consisting of
cancer, immunosuppressed conditions, or an infectious disease cause
by a bacterium, virus, protozoan or helminth.
31. A method for adoptive immunotherapy of a disease or disorder
characterized by over-activation, undesirable or aberrant
activation of an immune response comprising isolating a population
of CD4.sup.+CD45.sup.+ T cells from a subject to be treated,
activating the CD4.sup.+CD45.sup.+ T cells using the method of
claim 1, expanding the CD4.sup.+CD45.sup.+ T cells, and
administering the CD4.sup.+CD45.sup.+ T cells to the subject to be
treated in an amount effective to eliminate or reduce the risk or
delay the outset of conditions associated with undesirable
activation, over-activation or inappropriate or aberrant activation
of an immune response.
32. The method of claim 19, wherein the disease or disorder is
selected from the group consisting of allergic disease, autoimmune
diseases or disorders, graft rejection or graft-versus-host
disease.
33. The method of claim 19, wherein the disease or disorder is
cancer, and wherein the amount is effective to delay or inhibit
tumor growth.
34. The method of claim 20, wherein CD8+ T cells are preferentially
activated, as compared to CD4.sup.+ T cells.
35. An artificial antigen-presenting cell (aAPC) composition
comprising polymeric nano- or microparticles, at least one cytokine
encapsulated in or incorporated into the nano- or microparticles,
coupling agents bound to or incorporated into the surface of the
nano- or microparticles, at least one T cell receptor activator
bound to the nano- or microparticles, and at least one
co-stimulatory molecule bound to the nano- or microparticles.
36. The aAPC composition of claim 35, wherein the T cell receptor
activators and the co-stimulatory molecules are bound to the nano-
or microparticles by the coupling agents.
37. The aAPC composition of claim 35, wherein the coupling agents
are conjugated to affinity tags.
38. The aAPC composition of claim 37, wherein the coupling agents
are bound to the T cell receptor activators and the co-stimulatory
molecules by the non-covalent interaction of the affinity tag
conjugated to the coupling agents and complementary affinity tags
conjugated to the T cell receptor activators and the co-stimulatory
molecules.
39. The aAPC composition of claim 35, wherein the at least one
cytokine is selected from the group consisting of granulocyte
macrophage colony stimulating factor (GM-CSF), tumor necrosis
factor alpha (TNF.alpha.), tumor necrosis factor beta (TNF.beta.),
macrophage colony stimulating factor (M-CSF), interleukin-1 (IL-1),
interleukin-2 (IL-2), interleukin-4 (IL-4), interleukin-5 (IL-5),
interleukin-6 (IL-6), interleukin-10 (IL-10), interleukin-12
(IL-12), interleukin-15 (IL-15), interleukin-21 (IL-21), interferon
alpha (IFN.alpha.), interferon beta (IFN.beta.), interferon gamma
(IFN.gamma.), and IGIF, and variants and fragments thereof.
40. The aAPC composition of claim 35, wherein the coupling agents
are materials with a hydrophile-lipophile balance of less than
10.
41. The aAPC composition of claim 35, wherein the at least one T
cell receptor activator is a polyclonal T cell receptor
activator.
42. The aAPC composition of claim 35, wherein the at least one T
cell receptor activator comprises WIC molecules bound to peptide
antigens.
43. The aAPC composition of claim 35, wherein the at least one
co-stimulatory molecule is selected from the group consisting of
CD7, B7-1 (CD80), B7-2 (CD86), PD-L1, PD-L2, 4-1BBL, OX40L,
inducible co-stimulatory ligand (ICOS-L), intercellular adhesion
molecule (ICAM), CD2, CD5, CD9, CD30L, CD40, CD70, CD83, HLA-G,
MICA, MICB, HVEM, lymphotoxin beta receptor, 3/TR6, ILT3, ILT4,
HVEM, a ligand that specifically binds with B7-H3, a ligand that
specifically binds with CD83 and antibodies that specifically bind
with Toll ligand receptor, CD27, CD28, 4-1BB, OX40, CD30, CD40,
PD-1, ICOS, lymphocyte function-associated antigen-1 (LFA-1), CD2,
CD7, LIGHT, NKG2C and 87-H3 and variants and fragments thereof.
44. The aAPC composition of claim 35, wherein the polymeric nano-
or microparticles are microparticles.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to and benefit of U.S.
Provisional Patent Application No. 61/021,258 filed on Jan. 15,
2008, by Tarek Fahmy and Erin Steenblock, and where permissible is
incorporated by reference in its entirety.
FIELD OF THE INVENTION
[0003] The present disclosure generally relates to the field of
artificial antigen-presenting cells and methods of making and using
these compositions.
BACKGROUND OF THE INVENTION
[0004] The aim of any immunotherapeutic treatment is to minimize
nonspecific toxicity, thus utilizing the body's own mechanisms to
target and kill abnormal cells. Immunotherapy can be used to prime
and amplify antigen-specific lymphocytes either in vivo (active
iummunotherapy) or ex vivo prior to their infusion (adoptive
immunotherapy). Adoptive immunotherapy is a procedure whereby an
individual's own lymphocytes are expanded ex vivo and re-infused
back into the body. Both adoptive and active immunotherapy can be
used as therapeutic strategies for the treatment of viral infection
(Papadopoulos, et al., N. Engl. J. Med, 330(17):1185-91 (1994);
Savoldo, et al., Leuk Lymphoma, 39(5-6):455-64 (2000)), autoimmune
disease (Hori, et al., Adv. Immunol., 81:331-71 (2003); Karim, et
al., J. Immunol., 172(2):923-8 (2004)), or cancer (Dudley, et al.,
Nat. Rev. Cancer, 3(9):666-75 (2003); Riddell, et al., Cancer
Control, 9(2):114-22 (2002); Yee, et al., Proc. Natl. Acad. Sci.
USA., 99(25):16168-73 (2002)).
[0005] The process of antigen-specific activation, expansion and
differentiation that is essential to the establishment of immunity
is determined to a large extent by the interaction between T cells
and antigen-presenting cells (APCs). Efficient stimulation of
antigen-specific T cells depends on the interaction of the T cell
antigen receptor (TCR) with specific antigen in the form of a
peptide/major histocompatibility complex (pMHC) on APCs. In
addition to this recognition signal, co-stimulation through the B7
family of receptors on APCs, which engage the CD28 receptor and
related receptors on T cells, is known to amplify antigen-specific
T cell responses (Michel, et al., Immunity, 15(6):935-45
(2001)).
[0006] T cell activation and function is also influenced by
cytokines, the largest class of immunoregulatory molecules.
Cytokines are secreted by activated antigen presenting cells after
T cell encounters and impact expansion, survival, effector
function, and memory of stimulated T cells (Pardoll, Nat. Rev.
Immunol., 2(4):227-38 (2002); Fyfe, et al., J. Clin. Oncol.,
13(3):688-96 (1995); Schluns, et al., Nat. Rev. Immunol,
3(4):269-79 (2003)).
[0007] While natural APCs, notably dendritic cells (DCs), are the
most potent in initiating immune responses, their use in ex vivo
stimulation of antigen-specific immune responses in clinical
settings involving adoptive immunotherapy has been limited because
of issues related to the quality, expense, and time involved in
their isolation and culture (Oelke, et al., Nat. Med., 9(5):619-24
(2003)). Because T cell restriction necessitates the use of
autologous DCs, custom isolation must be carried out for individual
patient cases, limiting the generalization of this therapy. To
address this issue, artificial APCs ("aAPCs") have been proposed
based on cellular and acellular systems and have been tested in the
expansion of a number of specific T cell populations for the
treatment of a variety of disease states (Oelke, et al., Nat. Med.,
9(5):619-24 (2003); Kim, et al., Nat. Biotechnol., 22(4):403-10
(2004)).
[0008] Cellular aAPCs have been created from human leukemia cell
lines (Hirano, et al., Clin. Cancer Res., 12(10):2967-75 (2006);
Maus, et al., Nat. Biotechnol., 20(2):143-8 (2002)), insect cells
(Mitchell, et al., J. Clin. Oncol., 20(4):1075-86 (2002); Jackson,
et al., Proc. Natl. Acad. Sci. U.S.A., 89(24):12117-21 (1992); Sun,
et al., Immunity, 4(6):555-64 (1996)), and mouse fibroblasts
(Latouche, et al., Nat. Biotechnol., 18(4):405-9 (2000);
Schoenberger, et al., Cancer Res., 58(14):3094-100 (1998)).
Although physiological in nature, these systems require genetic
modifications in order to effectively present antigens and may
carry the risk for potential infection or tumorigenicity. Acellular
approaches, which use micron-size latex or magnetic beads (Oelke,
et al., Nat. Med., 9(5):619-24 (2003); Levine, et al., Science,
272(5270):1939-43 (1996); Tha, et al., J. Immunol. Methods,
249(1-2):111-9 (2001)) or lipid-based vesicles with immobilized
ligands (van Rensen, et al., Pharm. Res., 16(2):198-204 (1999);
Prakken, et al., Nat. Med., 6(12):1406-10 (2000); Thery, et al.,
Nat. Rev. Immunol., 2(8):569-79 (2002)), are attractive because of
the flexibility in tailoring the composition and density of ligand
presentation. While these platforms may eliminate the risk of
infection by utilizing synthetic constructs, they lack
biocompatibility and present safety risks if not removed prior to
re-infusion of the expanded cells into patients (Kim, et al., Nat.
Biotechnol., 22(4):403-10 (2004)). Also, there are currently no
aAPC technologies that exist that incorporate all of the necessary
signals for T cell activation in a safe, ready-to-use system that
could be rapidly modified for antigen-specific T cell activation
and expansion.
[0009] It is therefore an object of the invention to provide
modular microparticulate aAPC compositions which provide for
flexible addition and subtraction of elements.
[0010] It is another object of the invention to provide aAPCs and
methods of use thereof for in vivo or ex vivo activation and
expansion of lymphocytes, including T cells.
[0011] It is another object of the invention to provide
compositions and methods for active and adoptive immunotherapy of
cancer or an infection, such as a viral, bacterial, parasitic,
protozoan or fungal infection.
[0012] It is another object of the invention to provide
compositions and methods for the treatment of autoimmune disorders,
graft rejection and graft-versus-host-disease.
SUMMARY OF THE INVENTION
[0013] Modular aAPCs and methods of their manufacture and use are
provided. The modular design of these polymeric aAPCs, which
involves flexible addition and subtraction of functional elements
including antigen-specific and polymeric T cell receptor
activators, co-stimulatory and adhesion molecules, and cytokines
allows for exquisite control over the signals provided to T cells
by natural APCs.
[0014] The modular aAPCs are constructed from polymeric nano- or
microparticles. The external surface of the polymeric aAPCs are
modified by conjugating to the surface of the microparticle a
coupling agent. The coupling agent is preferably present in high
density on the surface of the aAPC. Coupling agents preferably are
molecules that match the polymer phase hydrophile-lipophile
balance. The coupling agents can be fatty acids, hydrophobic or
amphipathic peptides, or hydrophobic polymers. Coupling agents
provide substrates that facilitate the modular assembly and
disassembly of functional elements to the aAPCs. The coupling
agents can be conjugated to affinity tags which allow for the
modular assembly and disassembly of functional elements conjugated
to complementary affinity tags.
[0015] Functional elements that can be associated with the
polymeric aAPCs include antigen-specific and polyclonal T cell
receptor activators, co-stimulatory molecules and adhesion
molecules. Antigen-specific T cell receptor activators are
antigen-presenting molecules that have determinants that match that
of a selected subject. The antigen-presenting molecules can be
MHC/HLA class I or class II molecules. The antigen-presenting
molecules bind to antigens that can be peptides, polypeptides,
proteins, polysaccharides, saccharides, lipids, nucleic acids,
haptens or combinations thereof. In preferred embodiments the
antigens (or antigenic fragment or epitope) are short peptides
about 5-40 amino acids in length. The antigens can be viral
antigens, bacterial antigens, parasite antigens, allergens or
environmental antigens, tumor antigens, self antigens or
autoantigens. Polyclonal T cell receptor activators include
mitogenic lectins and antibodies that crosslink the T cell receptor
complex.
[0016] The aAPCs also contain cytokines encapsulated in or
incorporated into the polymeric microparticles. Incorporation of
cytokines into the polymeric microparticles allows for paracrine
release of the cytokines to T cells, thus recapitulating the
interaction with natural APCs. The examples demonstrate that
paracrine release of cytokines from aAPCs enhances T cell
activation and proliferation with a lesser concentration of
cytokine relative to exogenous administration. The examples also
demonstrate that paracrine release of IL-2 from aAPCs results in
the preferential expansion of CD8.sup.+ T cells, as compared to
CD4.sup.+ T cells. As a result, the disclosed aAPCs, which release
cytokines to T cells in a paracrine manner, are more effective than
previous artificial APCs at expanding cytotoxic T lymphocytes.
[0017] The ability of these aAPCs to release cytokines in a
controlled manner, coupled with their modular nature and ease of
ligand attachment, results in an ideal, tunable APC capable of
stimulating and expanding primary T cells. These aAPCs represent
true "off-the-shelf" technology amenable to long-term storage and
primed for immediate use.
[0018] Methods of using polymeric aAPCs in vivo for active
immunotherapy, and ex vivo, for adoptive immunotherapy, are also
provided. The methods can be used to prophylactically or
therapeutically to activate T cells. The methods can be used in
subjects infected with or exposed to infectious agents, subjects
with or at risk of developing malignant tumors, and subjects with
immunosuppressed conditions. The aAPCs may also be useful to induce
tolerance. The aAPCs are also useful in methods for treating or
preventing autoimmune diseases and disorders, allergic reactions,
graft rejection and graft-versus-host disease by adoptive
immunotherapy using aAPCs. In these methods, regulatory T cells
(Tregs) are activated by aAPCs. When administered to the subject,
Tregs actively and dominantly inhibit the activation and effector
functions of autoreactive T cells. Another method provided herein
includes the use of aAPCs to activate and expand cytotoxic T cells
specific for IgE or CD40L antigens.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1A is a bar graph showing size distributions for
microparticles. Data are presented as the number of particles
having certain diameters (.mu.m).
[0020] FIG. 1B is a bar graph showing size distributions for
nanoparticles. Data are presented as the number of particles having
certain diameters (nm).
[0021] FIG. 2 is a line graph showing viability of B6 splenocytes
exposed to varying concentrations of untargeted microparticles in
the presence of anti-CD3 and anti-CD28 for 72 hours. Proliferation
was assessed by the Cell Titer Blue Viability assay. Data are
expressed as viability (percent of control) as a function of
concentration of particles (.mu.g/ml).
[0022] FIG. 3 is a bar graph showing binding of biotin-conjugated
anti-CD3 antibody to micro- and nano-aAPCs with and without
(control) avidin. aAPCs were incubated with low (14 .mu.g/ml) and
high (56 .mu.g/ml) concentrations of anti-CD3 and bound protein
content was assessed by Micro BCA Protein assay. Data are expressed
as the percent of bound anti-CD3 for each condition tested.
[0023] FIG. 4 is a line graph showing the secretion of IL-2 from
OT-1 CD8+ T cells stimulated using micro- and nanoparticle aAPCs
coupled to biotinylated MHC-K.sup.b dimers loaded with the cognate
OVA SIINFEKL peptide derived from ovalbumin (OVA.sub.257-264)
(.sup.SIINK.sup.b) or noncognate OVA SIYRYYGL peptide
(.sup.SIYK.sup.b). Assembled aAPCs were serially diluted and
exposed to a constant number of OT-I CD8.sup.+ T cells. Activation
was assessed by measuring IL-2 levels from cell culture
supernatant. Data are presented for microparticle aAPCs coupled to
biotinylated MHC-.sup.SIINK.sup.b (-.DELTA.-) or biotinylated
MHC-.sup.SIYK.sup.b (-.diamond.-), nanoparticles coupled to
biotinylated MHC-.sup.SIINK.sup.b (-.box-solid.-), or soluble
MHC-.sup.SIINK.sup.b (-.largecircle.-). Data are expressed as the
concentration of secreted IL-2 (pg/ml) as a function of MHC
concentration (ng/ml).
[0024] FIG. 5A is a line graph showing the secretion of INF-.gamma.
from primary B6 splenocytes stimulated using microparticle aAPCs
presenting anti-CD3 alone (-.box-solid.-) or anti-CD3 and anti-CD28
(-.DELTA.-) in a 1:1 molar ratio. Data are expressed as the
concentration of secreted INF-.gamma. (pg/ml) as a function of
anti-CD3 antibody concentration (ng/ml).
[0025] FIG. 5B is a line graph showing the proliferation of primary
B6 splenocytes stimulated using microparticle aAPCs presenting
anti-CD3 alone (-.box-solid.-) or anti-CD3 and anti-CD28
(-.DELTA.-) in a 1:1 molar ratio. Data are expressed as the number
of cells per ml as a function of anti-CD3 antibody concentration
(ng/ml).
[0026] FIG. 5C is a line graph showing the secretion of IL-2 from
primary B6 splenocytes stimulated using microparticle aAPCs
presenting anti-CD3 alone (-.box-solid.-) or anti-CD3 and anti-CD28
(-.DELTA.-) in a 1:1 molar ratio. Data are expressed as the
concentration of secreted IL-2 (pg/ml) as a function of anti-CD3
antibody concentration (ng/ml).
[0027] FIG. 5D is a line graph showing the secretion of IL-2 from
OT-1 CD8+ T cells stimulated in an antigen-specific manner using
microparticle aAPCs presenting MHC-.sup.SIINK.sup.b alone
(-.largecircle.-) or MHC-.sup.SIINK.sup.b and anti-CD28
(-.diamond.-) in a 1:1 molar ratio. Data are expressed as the
concentration of secreted IL-2 (pg/ml) as a function of MHC
concentration (ng/ml).
[0028] FIG. 6A is a line graph showing the kinetics of controlled
release of encapsulated recombinant human IL-2 (rhIL-2) from
various microparticle aAPC formulations. Micropartcles were
generated by double emulsion water-in-oil-in-water (w/o/w)
technique (-.DELTA.-) or by single emulasion solid-in-oil-in-water
(s/o/w) technique where the rhIL-2 was either stabilized prior to
encapsulation with trehalose (-.largecircle.-) or not
(-.box-solid.-). Data are expressed as concentration of released
rhIL-2 (pg/mg polymer) as a function of time (days). The error bars
represent standard deviation with n=3. Data were fit using a
two-phase exponential association function.
[0029] FIG. 6B is a bar graph showing the concentration of aAPCs
producing peak IFN-g secretion B6 splenocytes for each of the
indicated formulations. The effect of delivering rhIL-2 from
microparticle aAPCs was investigated by stimulating B6 splenocytes
(5.times.10.sup.5 cell/mL) far 60 hours at 37.degree. C. aAPCs
presenting anti-CD3 and anti-CD28 with varying IL-2 loads
(dependent on the method of encapsulation) were titrated to
determine the optimal concentration for stimulating IFN-.gamma.
production by 136 splenocytes.
[0030] FIG. 6C is a line graph showing release of IFN-.gamma. from
B6 splenocytes stimulated by aAPCs with encapsulated IL-2
(-.largecircle.-) was compared to aAPCs with exogenous addition of
the cytokine (-.box-solid.-) or aAPCs without IL-2 present
(-.largecircle.-). Titration of all groups began at 5 mg/mL of
microparticles (effective antibody concentration of 5 .mu.g/mL).
Data are expressed as the concentration of IFN-.gamma. (pg/ml) as a
function of anti-CD3 concentration (ng/ml).
[0031] FIG. 6D is a line graph showing release of IFN-.gamma. from
86 splenocytes stimulated by aAPCs with aAPCs with exogenous IL-2
(-.largecircle.-) or with encapsulated IL-2. Particles with
encapsulated IL-2 were either applied to cells fresh
(-.box-solid.-) or were allowed to release IL-2 at 37.degree. C.
for 7 days, then washed before loading of antibodies and
stimulation of cells (-.DELTA.-).
[0032] FIG. 6E is a bar graph showing release of IFN-.gamma. from
B6 splenocytes stimulated by soluble anti-CD3 and anti-CD28
antibodies, aAPCs loaded with anti-CD3 and anti-CD28 antibodies
with encapsulated IL-2, aAPCs loaded with anti-CD3 and anti-CD28
antibodies plus exogenous IL-2, and Dynal magnetic beads coated
with avidin plus exogenous IL-2.
[0033] FIG. 7A is a series of histograms showing cell division of
B6 T cell splenocytes stimulated with soluble anti-CD3 and
anti-CD28 antibodies or with aAPCs loaded with anti-CD3 and
anti-CD28 antibodies with either encapsulated or exogenously added
IL-2 as indicated. Proliferation was assessed by CFSE staining. The
numbers in the upper left-hand corner indicate the number of
divided cells for each condition tested.
[0034] FIG. 7B is a bar graph showing proliferation of 136 T cell
splenocytes at days 5, 6 and 7 following activation with the
formulations specified for FIG. 7A. Data are expressed as the total
number of cells (.times.10.sup.7) for each formulation tested.
[0035] FIG. 5A is a bar graph showing expression of CD25 on B6 T
cell splenocytes activated by isotype control antibodies, soluble
anti-CD3 and anti-CD28 antibodies or with aAPCs loaded with
anti-CD3 and anti-CD28 antibodies with either encapsulated or
exogenously added IL-2 as indicated. CD25 expression was determined
by flow cytometry using anti-CD25-PE and anti-CD8 antibodies and
gating for CD8.sup.+ cells. Data are expressed as the mean PE
fluorescence intensity.
[0036] FIG. 8B is a bar graph showing the relative proportions of
CD4.sup.+ and CD8.sup.+ T cells after stimulation of B6 T cell
splenocytes activated by soluble anti-CD3 and anti-CD28 antibodies
with or without exogenous IL-2, or with Dynal beads loaded with
anti-CD3 and anti-CD28 antibodies with or without exogenous IL-2,
or with aAPCs loaded with anti-CD3 and anti-CD28 antibodies with
either encapsulated or exogenously added IL-2 as indicated.
[0037] FIG. 9 is a bar graph showing the tumor area (cm.sup.2) in
mice as a function of days after injection with B16 melanoma tumor
cells. Mice were treated either with plain particles (cross-hatched
bars), particles coated with anti-CD3 and anti-CD28 antibodies
(closed bars), or particles encapsulating IL-2 coated with anti-CD3
and anti-CD28 antibodies (hatched bars).
DETAILED DESCRIPTION OF THE INVENTION
I. Definitions
[0038] Terms defined herein have meanings as commonly understood by
a person of ordinary skill in the art. Terms such as "a", "an" and
"the" are not intended to refer to only a singular entity, but
include the general class of which a specific example may be used
for illustration.
[0039] "Affinity tags" are defined herein as molecular species
which form highly specific, non-covalent, physiochemical
interactions with defined binding partners. Affinity tags which
form highly specific, non-covalent, physiochemical interactions
with one another are defined herein as "complementary".
[0040] "Coupling agents" are defined herein as molecular entities
which associate with polymeric nanoparticles and provide substrates
that facilitate the modular assembly and disassembly of functional
elements onto the nanoparticle. Coupling agents can be conjugated
to affinity tags. Affinity tags allow for flexible assembly and
disassembly of functional elements which are conjugated to affinity
tags that form highly specific, noncovalent, physiochemical
interactions with affinity tags conjugated to adaptor elements.
Coupling agents can also be covalently coupled to functional
elements in the absence of affinity tags.
[0041] An "antigen" is defined herein as a molecule which contains
one or more epitopes that will stimulate a host's immune system to
make a cellular antigen-specific immune response, and/or a humoral
antibody response. Antigens can be peptides, proteins,
polysaccharides, saccharides, lipids, nucleic acids, and
combinations thereof. The antigen can be derived from a virus,
bacterium, parasite, plant, protozoan, fungus, tissue or
transformed cell such as a cancer or leukemic cell and can be a
whole cell or immunogenic component thereof, e.g., cell wall
components. An antigen may be an oligonucleotide or polynucleotide
which expresses an antigen. Antigens can be natural or synthetic
antigens, for example, haptens, polyepitopes, flanking epitopes,
and other recombinant or synthetically derived antigens (Bergmann,
et al., Eur. J. Immunol., 23:2777-2781 (1993); Bergmann, et al., J.
Immunol., 157:3242-3249 (1996); Suhrbier, Immunol. and Cell Biol.,
75:402-408 (1997).
[0042] A "tumor-specific antigen" is defined herein as an antigen
that is unique to tumor cells and does not occur in or on other
cells in the body.
[0043] A "tumor-associated antigen" is defined herein as an antigen
that is not unique to a tumor cell and is also expressed in or on a
normal cell under conditions that fail to induce an immune response
to the antigen.
[0044] "APCs" are defined herein as highly specialized cells that
can process antigens and display their peptide fragments on the
cell surface together with molecules required for lymphocyte
activation. The major APCs for T cells are dendritic cells,
macrophages and B cells. The major APCs for B cells are follicular
dendritic cells.
[0045] As used herein the term "isolated" is meant to describe a
compound of interest (e.g., either a polynucleotide or a
polypeptide) that is in an environment different from that in which
the compound naturally occurs, e.g., separated from its natural
milieu such as by concentrating a peptide to a concentration at
which it is not found in nature. "Isolated" is meant to include
compounds that are within samples that are substantially enriched
for the compound of interest and/or in which the compound of
interest is partially or substantially purified.
[0046] As used herein, the term "polypeptide" refers to a chain of
amino acids of any length, regardless of modification (e.g.,
phosphorylation or glycosylation).
[0047] As used herein, a "variant" polypeptide contains at least
one amino acid sequence alteration (addition, deletion,
substitution, preferably conservative i.e., not substantially
changing the function except in magnitude) as compared to the amino
acid sequence of the corresponding wild-type polypeptide.
[0048] As used herein, an "amino acid sequence alteration" can be,
for example, a substitution, a deletion, or an insertion of one or
more amino acids.
[0049] As used herein, a "vector" is a replicon, such as a plasmid,
phage, or cosmid, into which another DNA segment may be inserted so
as to bring about the replication of the inserted segment. The
vectors described herein can be expression vectors.
[0050] As used herein, an "expression vector" is a vector that
includes one or more expression control sequences
[0051] As used herein, an "expression control sequence" is a DNA
sequence that controls and regulates the transcription and/or
translation of another DNA sequence.
[0052] As used herein, "operably linked" means incorporated into a
genetic construct so that expression control sequences effectively
control expression of a coding sequence of interest.
[0053] As used herein, a "fragment" of a polypeptide refers to any
subset of the polypeptide that is a shorter polypeptide of the full
length protein. Generally, fragments will be five or more amino
acids in length.
[0054] As used herein, "conservative" amino acid substitutions are
substitutions wherein the substituted amino acid has similar
structural or chemical properties.
[0055] As used herein, "non-conservative" amino acid substitutions
are those in which the charge, hydrophobicity, or bulk of the
substituted amino acid is significantly altered.
[0056] As used herein, "isolated nucleic acid" refers to a nucleic
acid that is separated from other nucleic acid molecules that are
present in a mammalian genome, including nucleic acids that
normally flank one or both sides of the nucleic acid in a mammalian
genome.
[0057] As used herein with respect to nucleic acids, the term
"isolated" includes any non-naturally-occurring nucleic acid
sequence, since such non-naturally-occurring sequences are not
found in nature and do not have immediately contiguous sequences in
a naturally-occurring genome.
[0058] As used herein, the term "host cell" refers to prokaryotic
and eukaryotic cells into which a recombinant expression vector can
be introduced.
[0059] As used herein, "transformed" and "transfected" encompass
the introduction of a nucleic acid (e.g. a vector) into a cell by a
number of techniques known in the art.
[0060] The terms "individual", "host", "subject", and "patient" are
used interchangeably herein.
[0061] As used herein, the phrase that a molecule "specifically
binds" to a target refers to a binding reaction which is
determinative of the presence of the molecule in the presence of a
heterogeneous population of other biologics. Thus, under designated
immunoassay conditions, a specified molecule binds preferentially
to a particular target and does not bind in a significant amount to
other biologics present in the sample. Specific binding of an
antibody to a target under such conditions requires the antibody be
selected for its specificity to the target. A variety of
immunoassay formats may be used to select antibodies specifically
immunoreactive with a particular protein. For example, solid-phase
ELISA immunoassays are routinely used to select monoclonal
antibodies specifically immunoreactive with a protein. See, e.g.,
Harlow and Lane (1988) Antibodies, A Laboratory Manual, Cold Spring
Harbor Publications, New York, for a description of immunoassay
formats and conditions that can be used to determine specific
immunoreactivity. Specific binding between two entities means an
affinity of at least 10.sup.6, 10.sup.7, 10.sup.8, 10.sup.9, or
10.sup.1.degree. Affinities greater than 10.sup.8 M.sup.-4 are
preferred.
[0062] As used herein, the terms "antibody" or "immunoglobulin" are
used to include intact antibodies and binding fragments thereof.
Typically, fragments compete with the intact antibody from which
they were derived for specific binding to an antigen fragment
including separate heavy chains, light chains Fab, Fab'
F(ab').sub.2, Fabc, and Fv. Fragments are produced by recombinant
DNA techniques, or by enzymatic or chemical separation of intact
immunoglobulins. The term "antibody" also includes one or more
immunoglobulin chains that are chemically conjugated to, or
expressed as, fusion proteins with other proteins. The term
"antibody" also includes bispecific antibody. A bispecific or
bifunctional antibody is an artificial hybrid antibody having two
different heavy/light chain pairs and two different binding sites.
Bispecific antibodies can be produced by a variety of methods
including fusion of hybridomas or linking of Fab' fragments. See,
e.g., Songsivilai & Lachmann, Clin. Exp. Immunol., 79:315-321
(1990); Kostelny et al., J. Immunol., 148, 1547-1553 (1992).
[0063] As used herein, the terms "epitope" or "antigenic
determinant" refer to a site on an antigen to which B and/or T
cells respond. B-cell epitopes can be formed both from contiguous
amino acids or noncontiguous amino acids juxtaposed by tertiary
folding of a protein. Epitopes formed from contiguous amino acids
are typically retained on exposure to denaturing solvents whereas
epitopes formed by tertiary folding are typically lost on treatment
with denaturing solvents. An epitope typically includes at least 3,
and more usually, at least 5 or 8-10 amino acids, in a unique
spatial conformation. Methods of determining spatial conformation
of epitopes include, for example, x-ray crystallography and
2-dimensional nuclear magnetic resonance. See, e.g., Epitope
Mapping Protocols in Methods in Molecular Biology, Vol. 66, Glenn
E. Morris, Ed. (1996). Antibodies that recognize the same epitope
can be identified in a simple immunoassay showing the ability of
one antibody to block the binding of another antibody to a target
antigen. T-cells recognize continuous epitopes of about nine amino
acids for CD8 cells or about 13-15 amino acids for CD4 cells. T
cells that recognize the epitope can be identified by in vitro
assays that measure antigen-dependent proliferation, as determined
by .sup.3H-thymidine incorporation by primed T cells in response to
an epitope (Burke et al., J. Inf. Dis. 170, 1110-19 (1994)), by
antigen-dependent killing (cytotoxic T lymphocyte assay, Tigges et
al., J. Immunol. 156, 3901-3910) or by cytokine secretion.
[0064] As used herein, the terms "immunologic", "immunological" or
"immune" response is the development of a humoral (antibody
mediated) and/or a cellular (mediated by antigen-specific T cells
or their secretion products) response directed against an antigen.
Such a response can be an active response induced by administration
of immunogen or a passive response induced by administration of
antibody or primed T-cells. A cellular immune response is elicited
by the presentation of polypeptide epitopes in association with
Class T or Class II MHC molecules to activate antigen-specific
CD4.sup.+ T helper cells and/or CD8.sup.+ cytotoxic T cells. The
response may also involve activation of monocytes, macrophages, NK
cells, basophils, dendritic cells, astrocytes, microglia cells,
eosinophils or other components of innate immunity. The presence of
a cell-mediated immunological response can be determined by
proliferation assays (CD4.sup.+ T cells) or CTL (cytotoxic T
lymphocyte) assays. The relative contributions of humoral and
cellular responses to the protective or therapeutic effect of an
immunogen can be distinguished by separately isolating antibodies
and T-cells from an immunized syngeneic animal and measuring
protective or therapeutic effect in a second subject.
[0065] As used herein, a "costimulatory polypeptide" or a
"costimulatory molecule" is a polypeptide that, upon interaction
with a cell-surface molecule on T cells, enhances T cell responses,
enhances proliferation of T cells, enhances production and/or
secretion of cytokines by T cells, stimulates differentiation and
effector functions of T cells or promotes survival of T cells
relative to T cells not contacted with a costimulatory peptide.
[0066] The terms "individual", "host", "subject", and "patient" are
used interchangeably herein, and refer to a mammal, including, but
not limited to, murines, simians, humans, mammalian farm animals,
mammalian sport animals, and mammalian pets.
II. aAPC Compositions
[0067] T cell responses are mediated by the signals received from
APCs (Pardoll, Nat. Rev. Immunol., 2(4):227-38 (2002)). Multivalent
contacts between natural APCs and T cells are necessary to
facilitate avid interactions leading to efficient stimulation of T
cells (Fahmy, et al., Immunity, 14(2):135-43 (2001)). Efficient
stimulation of antigen-specific T cells depends on the interaction
of the T cell antigen receptor (TCR) with specific antigen in the
form of a peptide/major histocompatibility complex (pMHC) on APCs.
In addition to this recognition signal, co-stimulation through the
B7 family of receptors on APCs, which engage the CD28 receptor and
related receptors on T cells, is known to amplify antigen-specific
T cell responses (Michel, et al., Immunity, 15(6):935-45 (2001)).
Finally, cytokines, the largest class of immunoregulatory
molecules, are secreted by activated antigen presenting cells after
T cell encounters and impact expansion, survival, effector
function, and memory of stimulated T cells (Pardoll, Nat. Rev.
Immunol., 2(4):227-38 (2002); Fyfe, et al., J Clin. Oncol.,
13(3):688-96 (1995); Schluns, et al., Nat. Rev. Immunol.,
3(4):269-79 (2003)). No other aAPC technologies exist that
incorporate all three signals in a safe, ready-to-use system that
could be rapidly modified for antigen-specific T cell
expansion.
[0068] Modular aAPCs are constructed from polymeric nano- or
microparticles. The modular design of these polymeric aAPCs, which
involves flexible addition and subtraction of functional elements
including antigen-specific and polymeric T cell receptor
activators, co-stimulatory and targeting molecules, and cytokines,
allows for control over the signals provided to T cells by natural
APCs. The ability of these aAPCs to release cytokines in a
controlled manner, coupled with the ease of ligand attachment,
results in an ideal, tunable aAPC capable of stimulating and
expanding primary T cells. These aAPCs represent true
"off-the-shelf" technology amenable to long-term storage and primed
for immediate use.
[0069] A. Polymeric Micro- and Nanoparticles
[0070] As used herein, microparticles generally refers to both
microparticles in the range of between 0.5 and 1000 microns and
nanoparticles in the range of between 50 nm to less than 0.5 nm,
preferably having a diameter that is between 1 and 20 microns or
having a diameter that is between 50 and 500 nm, respectively.
Microparticles and nanoparticles are also referred to more
specifically. As the examples below demonstrate, it has been
discovered that microparticulate aAPCs are more efficient than
nanoparticulate aAPCs at stimulating T cell activation. Therefore,
in a preferred embodiment, the polymeric aAPCs are
microparticles.
[0071] The polymer that forms the core of the modular aAPC may be
any biodegradable or non-biodegradable synthetic or natural
polymer. In a preferred embodiment, the polymer is a biodegradable
polymer. Polymeric systems have several features that make them
ideal materials for the fabrication of a modular aAPC: 1) control
over the size range of fabrication, down to 100 nm or less; 2)
reproducible biodegradability without the addition of enzymes or
cofactors; 3) capability for sustained release of an encapsulated,
protected cytokine or chemokine over a period in the range of days
to months by varying factors such as the monomer ratios or polymer
size, for example, polylactic acid) (PLA) to poly(glycolic acid)
(PGA) copolymer ratios, potentially abrogating the booster
requirement (Gupta, et al., Adv. Drug Deliv. Rev., 32(3):225-246
(1998); Kohn, et al., J. Immunol. Methods, 95(1):31-8 (1986);
Langer, et al., Adv. Drug Deliv. Rev., 28(1):97-119 (1997); Jiang,
et al., Adv. Drug Deliv. Rev., 57(3):391-410)), well-understood
fabrication methodologies that offer flexibility over the range of
parameters that can be used for fabrication, including choices of
the polymer material, solvent, stabilizer, and scale of production;
and 5) control over surface properties facilitating the
introduction of modular functionalities into the surface.
[0072] Examples of preferred biodegradable polymers include
synthetic polymers that degrade by hydrolysis such as poly(hydroxy
acids), such as polymers and copolymers of lactic acid and glycolic
acid, polyanhydrides, poly(ortho)esters, polyesters, polyurethanes,
poly(butic acid), poly(valeric acid), poly(caprolactone),
poly(hydroxyalkanoates), and poly(lactide-co-caprolactone).
[0073] Preferred natural polymers include alginate and other
polysaccharides, collagen, albumin and other hydrophilic proteins,
zein and other prolamines and hydrophobic proteins, copolymers and
mixtures thereof. In general, these materials degrade either by
enzymatic hydrolysis or exposure to water in vivo, by surface or
bulk erosion.
[0074] In some embodiments, non-biodegradable polymers can be used,
especially hydrophobic polymers. Examples of preferred
non-biodegradable polymers include ethylene vinyl acetate,
poly(meth) acrylic acid, copolymers of maleic anhydride with other
unsaturated polymerizable monomers, poly(butadiene maleic
anhydride), polyamides, copolymers and mixtures thereof, and
dextran, cellulose and derivatives thereof.
[0075] Other suitable biodegradable and non-biodegradable polymers
include, but are not limited to, polyanhydrides, polyamides,
polycarbonates, polyalkylenes, polyalkylene oxides such as
polyethylene glycol, polyalkylene terepthalates such as
poly(ethylene terephthalate), polyvinyl alcohols, polyvinyl ethers,
polyvinyl esters, polyethylene, polypropylene, poly(vinyl acetate),
poly vinyl chloride, polystyrene, polyvinyl halides,
polyvinylpyrrolidone, polymers of acrylic and methacrylic esters,
polysiloxanes, polyurethanes and copolymers thereof, modified
celluloses, alkyl cellulose, hydroxyalkyl celluloses, cellulose
ethers, cellulose esters, nitro celluloses, cellulose acetate,
cellulose propionate, cellulose acetate butyrate, cellulose acetate
phthalate, carboxyethyl cellulose, cellulose triacetate, cellulose
sulfate sodium salt, and polyacrylates such as poly(methyl
methacrylate), poly(ethylmethacrylate), poly(butylmethacrylate),
poly(isobutylmethacrylate), poly(hexylmethacrylate),
poly(isodecylmethacrylate), poly(lauryl methacrylate), poly(phenyl
methacrylate), poly(methyl acrylate), poly(isopropyl acrylate),
poly(isobutyl acrylate), poly(octadecyl acrylate). The polymer may
be a bioadhesive polymer that is hydrophilic or hydrophobic.
Hydrophilic polymers include CARBOPOL.TM. (a high molecular weight,
crosslinked, acrylic acid-based polymers manufactured by
NOVEON.TM.), polycarbophil, cellulose esters, and dextran.
[0076] The foregoing materials may be used alone, as physical
mixtures (blends), or as co-polymers. In a preferred embodiment,
the aAPCs are formed of polymers fabricated from polylactides (PLA)
and copolymers of lactide and glycolide (PLGA). These have
established commercial use in humans and have a long safety record
(Jiang, et al., Adv. Drug Deliv. Rev., 57(3):391-410); Aguado and
Lambert, Immunobiology, 184(2-3):113-25 (1992); Bramwell, et al.,
Adv. Drug Deity. Rev., 57(9):1247-65 (2005)).
[0077] Rate controlling polymers may be included in the polymer
matrix or in the coating on the formulation. Examples of rate
controlling polymers that may be used are
hydroxypropylmethylcellulose (HPMC) with viscosities of either 5,
50, 100 or 4000 cps or blends of the different viscosities,
ethylcellulose, methylmethacrylates, such as EUDRAGIT.RTM. RS100,
EUDRAGIT.RTM. RL100, EUDRAGIT.RTM. NE 30D (supplied by Rohm
America). Gastrosoluble polymers, such as EUDRAGIT.RTM. E100 or
enteric polymers such as EUDRAGIT.RTM. L100-55D, L100 and S100 may
be blended with rate controlling polymers to achieve pH dependent
release kinetics. Other hydrophilic polymers such as alginate,
polyethylene oxide, carboxymethylcellulose, and
hydroxyethylcellulose may be used as rate controlling polymers.
[0078] These polymers can be obtained from sources such as Sigma
Chemical Co., St. Louis, Mo.; Polysciences, Warrenton, Pa.;
Aldrich, Milwaukee, Wis.; Fluka, Ronkonkoma, N.Y.; and BioRad,
Richmond, Calif., or can be synthesized from monomers obtained from
these or other suppliers using standard techniques.
[0079] B. Coupling Agents or Ligands
[0080] The external surface of the polymeric aAPCs may be modified
by conjugating to, or incorporating into, the surface of the
microparticle a coupling agent or ligand.
[0081] In a preferred embodiment, the coupling agent is present in
high density on the surface of the aAPC. As used herein, "high
density" refers to polymeric aAPCs having a high density of ligands
or coupling agents, which is preferably in the range of 1,000 to
10,000,000, more preferably 10,000-1,000.000 ligands per square
micron of microparticle surface area. This can be measured by
fluorescence staining of dissolved particles and calibrating this
fluorescence to a known amount of free fluorescent molecules in
solution.
[0082] Coupling agents associate with the polymeric aAPCs and
provide substrates that facilitate the modular assembly and
disassembly of functional elements to the aAPCs. Coupling agents or
ligands may associate with nanoparticles through a variety of
interactions including, but not limited to, hydrophobic
interactions, electrostatic interactions and covalent coupling.
[0083] In a preferred embodiment, the coupling agents are molecules
that match the polymer phase hydrophile-lipophile balance.
Hydrophile-lipophile balances range from 1 to 15. Molecules with a
low hydrophile-lipophile balance are more lipid loving and thus
tend to make a water in oil emulsion while those with a high
hydrophile-lipophile balance are more hydrophilic and tend to make
an oil in water emulsion. Fatty acids and lipids have a low
hydrophile-lipophile balance below 10.
[0084] Any amphiphilic polymer with a hydrophile-lipophile balance
in the range 1-10, more preferably between 1 and 6, most preferably
between 1 and up to 5, can be used as a coupling agent. Examples of
coupling agents which may associate with polymeric aAPCs via
hydrophobic interactions include, but are not limited to, fatty
acids, hydrophobic or amphipathic peptides or proteins, and
polymers. These classes of coupling agents may also be used in any
combination or ratio. In a preferred embodiment, the association of
adaptor elements with nanoparticles facilitates a prolonged
presentation of functional elements which can last for several
weeks.
[0085] In one embodiment, coupling agents can be conjugated to
affinity tags. Affinity tags are any molecular species which form
highly specific, noncovalent, physiochemical interactions with
defined binding partners. Affinity tags which form highly specific,
noncovalent, physiochemical interactions with one another are
defined herein as "complementary". Suitable affinity tag pairs are
well known in the art and include epitope/antibody, biotin/avidin,
biotin/streptavidin, biotin/neutravidin,
glutathione-S-transferase/glutathione, maltose binding
protein/amylase and maltose binding protein/maltose. Examples of
suitable epitopes which may be used for epitope/antibody binding
pairs include, but are not limited to, HA, FLAG, c-Myc,
glutatione-S-transferase, His.sub.6, GFP, DIG, biotin and avidin.
Antibodies (both monoclonal and polyclonal and antigen-binding
fragments thereof) which bind to these epitopes are well known in
the art.
[0086] Affinity tags that are conjugated to coupling agents allow
for highly flexible, modular assembly and disassembly of functional
elements which are conjugated to affinity tags which form highly
specific, noncovalent, physiochemical interactions with
complementary affinity tags which are conjugated to coupling
agents. Adaptor elements may be conjugated with a single species of
affinity tag or with any combination of affinity tag species in any
ratio. The ability to vary the number of species of affinity tags
and their ratios conjugated to adaptor elements allows for
exquisite control over the number of functional elements which may
be attached to the nanoparticles and their ratios.
[0087] In another embodiment, coupling agents are coupled directly
to functional elements in the absence of affinity tags, such as
through direct covalent interactions. Coupling agents can be
covalently coupled to at least one species of functional element.
Coupling agents can be covalently coupled to a single species of
functional element or with any combination of species of functional
elements in any ratio.
[0088] In a preferred embodiment coupling agents are conjugated to
at least one affinity tag that provides for assembly and
disassembly of modular functional elements which are conjugated to
complementary affinity tags. In a more preferred embodiment,
coupling agents are fatty acids that are conjugated with at least
one affinity tag. In a particularly preferred embodiment, the
coupling agents are fatty acids conjugated with avidin or
streptavidin. Avidin/streptavidin-conjugated fatty acids allow for
the attachment of a wide variety of biotin-conjugated functional
elements.
[0089] The coupling agents are preferably provided on, or in the
surface of, nanoparticles at a high density. This high density of
coupling agents allows for coupling of the polymeric aAPCs to a
variety of species of functional elements while still allowing for
the functional elements to be present in high enough numbers to be
efficacious.
[0090] i. Fatty Acids
[0091] The coupling agents may include fatty acids. Fatty acids may
be of any acyl chain length and may be saturated or unsaturated. In
a particularly preferred embodiment, the fatty acid is palmitic
acid. Other suitable fatty acids include, but are not limited to,
saturated fatty acids such as butyric, caproic, caprylic, capric,
lauric, myristic, stearic, arachidic and behenic acid. Still other
suitable fatty acids include, but are not limited to, unsaturated
fatty acids such as oleic, linoleic, alpha-linolenic, arachidonic,
eicosapentaenoic, docosahexaenoic and erucic acid.
[0092] ii. Hydrophobic or Amphipathic Peptides
[0093] The coupling agents may include hydrophobic or amphipathic
peptides. Preferred peptides should be sufficiently hydrophobic to
preferentially associate with the polymeric nanoparticle over the
aqueous environment. Amphipathic polypeptides useful as adaptor
elements may be mostly hydrophobic on one end and mostly
hydrophilic on the other end. Such amphipathic peptides may
associate with polymeric aAPCs through the hydrophobic end of the
peptide and be conjugated on the hydrophilic end to a functional
group.
[0094] iii. Hydrophobic Polymers
[0095] Coupling agents may include hydrophobic polymers. Examples
of hydrophobic polymers include, but are not limited to,
polyanhydrides, poly(ortho)esters, and polyesters such as
polycaprolactone.
[0096] C. Functional Elements to be Attached to the Surface of the
Polymeric aAPCs
[0097] Functional elements which associate with the polymeric APCs
through modular coupling agents function to target the APCs to T
cells and to recapitulate the interactions that occur between
natural APCs and T cells to elicit efficient activation and
expansion of T cells. Functional elements include antigen-specific
and polyclonal T cell receptor ligands, co-stimulatory molecules,
and T cell targeting and adhesion molecules.
[0098] Polymeric aAPCs may be associated with a single species of
functional element or may be associated with any combination of
disclosed functional elements in any ratio. Functional elements are
associated with aAPCs through coupling agents which directly
associate with the aAPCs. Functional elements may be directly or
covalently coupled to coupling agents or may bind to coupling
agents through complementary affinity tags conjugated to the
coupling agents and functional elements. Multiple different species
of functional elements may be associated with aAPCs, for instance,
by conjugating each species of functional element to a separate
species of affinity tag. These functional elements may then
associate with aAPCs coated with coupling agents conjugated to an
appropriate ratio of complementary affinity tags. Multiple species
of functional elements may also be associated with aAPCs by
covalently coupling each species of functional element at a desired
ratio to coupling agents.
[0099] In a preferred embodiment, functional elements are
conjugated to biotin. Biotin conjugation allows the functional
elements to interact with coupling agents conjugated with avidin,
neutravidin or streptavidin.
[0100] i. T cell Receptor Activators
[0101] a. Antigen-Specific T Cell Receptor Activators
[0102] Antigen molecules are recognized by the immune system after
internal processing by natural APCs (Lanzavecchia, Curr. Opin.
Immunol., 8:348-54 (1996)). In order to present an antigen, the
antigen is broken down into small peptidic fragments by enzymes
contained in vesicles in the cytoplasm of the APCs (Wick, et al.,
Immunol. Rev., 172:153-62 (1999); Lehner, et al., Curr. Biol., 8:
R605-8 (1998); Braciale, Curr. Opin. Immunol., 4:59-62 (1992)). The
enzymes are part of a complex of proteolytic enzymes called a
proteosome. Most cells have several different types of proteosomes
with differing combinations of specificities, which they use to
recycle their intracellular proteins. The peptides produced by the
proteosomes are generated in the cytosol and transported into the
Golgi, where they are linked to cellular major histocompatibility
complex (MHC) molecules. These are referred to as human leukocyte
antigens, or "HLAs", in human. MHC and HLA are used interchangeably
herein unless specified otherwise.
[0103] ii. HLA and MHC Molecules
[0104] In one embodiment, the aAPCs described herein contain
antigen-presenting molecules having determinants which match that
of a selected subject or which match any known antigen-presenting
molecule determinants. The antigen-presenting molecules may be
MHC/HLA class I or class II molecules.
[0105] There are two types of HLA molecules used for antigen
presentation, class I and class II molecules. HLA class I molecules
are expressed on the surface of all cells and HLA class II are
expressed on the surface of a specialized class of cells called
professional APCs. HLA class II molecules bind primarily to
peptides derived from proteins made outside of an APC, but can
present self (endogenous) antigens. In contrast, HLA class I
molecules bind to peptides derived from proteins made inside a
cell, including proteins expressed by an infectious agent (e.g.,
such as a virus) in the cell and by a tumor cell. When the HLA
class I proteins reach the surface of the cell these molecules will
thus display any one of many peptides derived from the cytosolic
proteins of that cell, along with normal "self" peptides being
synthesized by the cell. Peptides presented in this way are
recognized by T-cell receptors which engage T-lymphocytes in an
immune response against the antigens to induce antigen-specific
cellular immunity.
[0106] Class I transplantation antigens of the major
histocompatibility complex (MHC) or HLA are cell surface
glycoproteins which present antigens to cytotoxic T-cells. They are
heterodimeric and composed of a polymorphic, MHC-encoded,
approximately 45 kD heavy chain, which is non-covalently associated
with an approximately 12 kD .beta.-2 microglobulin (.beta.-2m)
light chain.
[0107] The extracellular portion of the MHC Class I heavy chain is
divided into three domains, .alpha.-1, .alpha.-2, and .alpha.-3,
each approximately 90 amino acids long and encoded on separate
exons. The .alpha.-3 domain and .beta.-2m are relatively conserved
and show amino-acid sequence homology to immunoglobulin constant
domains. The polymorphic .alpha.-1 and .alpha.-2 domains show no
significant sequence homology to immunoglobulin constant or
variable region, but do have weak sequence homology to each other.
The membrane-distal polymorphic .alpha.-1 (approximately 90 amino
acids) and .alpha.-2 (approximately 92 amino acids) domains each
include four anti-parallel, .beta.-pleated sheets bordered by one
.alpha.-helical regions, (the first from the .alpha.-1 and the
second from the .alpha.-2 domain). The .alpha.-2 domain is attached
to the less-polymorphic, membrane-proximal .alpha.-3 (approximately
92 amino acids) domain which is followed by a conserved
transmembrane (25 amino acids) and an intra-cytoplasmic
(approximately 30 amino acids) segment. The rat, mouse, and human
Class I MHC molecules are believed to have similar structural
characteristics based upon known nucleotide sequences of the
various MHC Class I molecules.
[0108] The classical class I gene family includes the highly
polymorphic human class I molecules HLA-A, -B, and --C, and murine
class I (i.e., H-2) molecules D, K, and L. A series of structural
relatives (non-classical class I molecules) has been found in
humans (e.g., HLA-E, -F, -G, -H, -I, and -J; and CD1) and mice (Q,
T, M, and CD1) (Shawar, et al., Annu. Rev. Immunol., 12:839-880
(1994)). These molecules have the typical structure of an
antigen-presenting molecule, where a polymorphic heavy chain is
noncovalently associated with the conserved .beta.2-M subunit.
[0109] In the case of human class I determinants, the determinant
can be a polypeptide encoded by any of the known HLA genetic loci,
as well as polypeptides encoded by genetic loci not yet discovered
so long as these can present antigen to a T cell in a manner
effective to activate the T cell receptor. Examples of known HLA
class I genetic loci include for HLA-A: A1, A2, A3, A11, A23, A24,
A25, A26, A28, A29, A30, A31, A32 and Aw33; for HLA-B: 137, B13,
B18, B27, B35, B37, B38, B39, Bw31, Bw42, B44, B45, B49, Bw50, B51,
Bw52, Bw53, Bw54, Bw55, Bw57, Bw58, Bw60, Bw61, Bw62, Bw63, Bw64
and Bw65; for HLA-C: Cw1.sup.b, Cw2, Cw3, Cw4, Cw5, Cw6, Cw7 and
Cw8.
[0110] The amino acid sequences of mammalian MHC class II alpha and
beta chain proteins, as well as nucleic acids encoding these
proteins, are also well known in the art and available from
numerous sources including GenBank. Exemplary sequences are
provided in Auffray, et al., Nature, 308(5957):327-333 (1984)
(human HLA DQ.alpha.); Larhamrnar, et al., Proc. Natl. Acad. Sci.
U.S.A., 80(23):7313-7317 (1983) (human LILA DQ.beta.); Das, et al.,
Proc. Natl. Acad. Sci. U.S.A., 80 (12): 3543-3547 (1983) (human HLA
DR.alpha.); Tonnelle, et al., EMBO J., 4(11):2839-2847 (1985)
(human HLA DR.beta.); Lawrence, et al., Nucleic Acids Res.,
13(20):7515-7528 (1985) (human HLA DP.alpha.); and Kelly and
Trowsdale, Nucl. Acids Res., 13(5):1607-1621 (1985) (human HLA
DP.beta.)
[0111] The MHC class I or class II polypeptide selected for use
with the aAPCs is typically encoded by genetic loci present in the
subject to be treated.
[0112] The MHC/HLA polypeptides disclosed herein include variant
polypeptides. As used herein, a "variant" polypeptide contains at
least one amino acid sequence alteration as compared to the amino
acid sequence of the corresponding wild-type polypeptide. An amino
acid sequence alteration can be, for example, a substitution, a
deletion, or an insertion of one or more amino acids.
[0113] A variant MHC/HLA polypeptide can have any combination of
amino acid substitutions, deletions or insertions. In one
embodiment, variant MHC/HLA polypeptides have an integer number of
amino acid alterations such that their amino acid sequence shares
at least 60, 70, 80, 85, 90, 95, 97, 98, 99, 99.5 or 100% identity
with an amino acid sequence of a corresponding wild type amino acid
sequence. In a preferred embodiment, variant MHC/HLA polypeptides
have an amino acid sequence sharing at least 60, 70, 80, 85, 90,
95, 97, 98, 99, 99.5 or 100% identity with the amino acid sequence
of a corresponding wild type polypeptide.
[0114] Percent sequence identity can be calculated using computer
programs or direct sequence comparison. Preferred computer program
methods to determine identity between two sequences include, but
are not limited to, the GCG program package, FASTA, BLASTP, and
TBLASTN (see, e.g., D. W. Mount, 2001, Bioinformatics: Sequence and
Genome Analysis, Cold Spring Harbor Laboratory Press, Cold Spring
Harbor, N.Y.). The BLASTP and TBLASTN programs are publicly
available from NCBI and other sources. The well-known Smith
Waterman algorithm may also be used to determine identity.
[0115] Exemplary parameters for amino acid sequence comparison
include the following: 1) algorithm from Needleman and Wunsch (J.
Mol. Biol., 48:443-453 (1970)); 2) BLOSSUM62 comparison matrix from
Hentikoff and Hentikoff (Proc. Natl. Acad. Sci. U.S.A.,
89:10915-10919 (1992)) 3) gap penalty=12; and 4) gap length
penalty=4. A program useful with these parameters is publicly
available as the "gap" program (Genetics Computer Group, Madison,
Wis.). The aforementioned parameters are the default parameters for
polypeptide comparisons (with no penalty for end gaps).
[0116] Alternatively, polypeptide sequence identity can be
calculated using the following equation: % identity=(the number of
identical residues)/(alignment length in amino acid residues)*100.
For this calculation, alignment length includes internal gaps but
does not include terminal gaps.
[0117] Amino acid substitutions in variant MHC/HLA polypeptides may
be "conservative" or "non-conservative". As used herein,
"conservative" amino acid substitutions are substitutions wherein
the substituted amino acid has similar structural or chemical
properties, and "non-conservative" amino acid substitutions are
those in which the charge, hydrophobicity, or bulk of the
substituted amino acid is significantly altered. Non-conservative
substitutions will differ more significantly in their effect on
maintaining (a) the structure of the peptide backbone in the area
of the substitution, for example, as a sheet or helical
conformation, (b) the charge or hydrophobicity of the molecule at
the target site, or (c) the bulk of the side chain.
[0118] Examples of conservative amino acid substitutions include
those in which the substitution is within one of the five following
groups: 1) small aliphatic, nonpolar or slightly polar residues
(Ala, Ser, Thr, Pro, Gly); 2) polar, negatively charged residues
and their amides (Asp, Asn, Glu, Gln); polar, positively charged
residues (His, Arg, Lys); large aliphatic, nonpolar residues (Met,
Leu, Ile, Val, Cys); and large aromatic resides (Phe, Tyr, Trp).
Examples of non-conservative amino acid substitutions are those
where 1) a hydrophilic residue, e.g., seryl or threonyl, is
substituted for (or by) a hydrophobic residue, e.g., leucyl,
isoleucyl, phenylalanyl, valyl, or alanyl; 2) a cysteine or proline
is substituted for (or by) any other residue; 3) a residue having
an electropositive side chain, e.g., lysyl, arginyl, or histidyl,
is substituted for (or by) an electronegative residue, e.g.,
glutamyl or aspartyl; or 4) a residue having a bulky side chain,
e.g., phenylalanine, is substituted for (or by) a residue that does
not have a side chain, e.g., glycine.
[0119] Variant MHC/HLA polypeptides may be modified by chemical
moieties that may be present in polypeptides in a normal cellular
environment, for example, phosphorylation, methylation, amidation,
sulfation, acylation, glycosylation, sumoylation and
ubiquitylation. Variant MHC/HLA polypeptides may also be modified
with a label capable of providing a detectable signal, either
directly or indirectly, including, but not limited to,
radioisotopes and fluorescent compounds.
[0120] Variant MHC/HLA polypeptides may also be modified by
chemical moieties that are not normally added to polypeptides in a
cellular environment. Such modifications may be introduced into the
molecule by reacting targeted amino acid residues of the
polypeptide with an organic derivatizing agent that is capable of
reacting with selected side chains or terminal residues. Another
modification is cyclization of the protein.
[0121] Examples of chemical derivatives of the polypeptides include
lysinyl and amino terminal residues derivatized with succinic or
other carboxylic acid anhydrides. Derivatization with a cyclic
carboxylic anhydride has the effect of reversing the charge of the
lysinyl residues. Other suitable reagents for derivatizing
amino-containing residues include imidoesters such as methyl
picolinimidate; pyridoxal phosphate; pyridoxal; chloroborohydride;
trinitrobenzenesulfonic acid; O-methylisourea; 2,4 pentanedione;
and transaminase-catalyzed reaction with glyoxylate. Carboxyl side
groups, aspartyl or glutamyl, may be selectively modified by
reaction with carbodiimides (R--N.dbd.C.dbd.N--R') such as
1-cyclohexyl-3-(2-morpholinyl-(4-ethyl)carbodiimide or
1-ethyl-3-(4-azonia-4,4-dimethylpentyl)carbodiimide. Furthermore,
aspartyl and glutamyl residues can be converted to asparaginyl and
glutaminyl residues by reaction with ammonia. Polypeptides may also
include one or more D-amino acids that are substituted for one or
more L-amino acids.
[0122] The variant MHC/HLA polypeptides disclosed herein may also
be coupled to other polypeptides to form fusion proteins. Provided
are variant MHC/HLA polypeptides having a first fusion partner
comprising all or a part of a MHC/HLA polypeptide fused (i)
directly to a second polypeptide or, (ii) optionally, fused to a
linker peptide sequence that is fused to the second polypeptide.
The presence of the fusion partner can alter the solubility,
affinity and/or valency of the polypeptide. MHC/HLA fusion proteins
described herein include any combination of amino acid alteration
(i.e. substitution, deletion or insertion), fragment, and/or
modification as described above.
[0123] iii. Antigens
[0124] Antigens can be peptides, polyeptides, proteins,
polysaccharides, saccharides, lipids, nucleic acids, or
combinations thereof. Because CTL epitopes usually comprise 8-10
amino acid long (Townsend, et al., Annu. Rev. Immunol., 7:601-624
(1989); Monaco, Cell, 54:777-785 (1992); Yewdell, et al., Adv. in
Immunol., 52:1-123 (1992)), in one embodiment, antigens are short
polypeptides. Antigenic polypeptides may be about 5 to 40 amino
acids, preferably 6 to 25 amino acids, more preferably 8 to 10
amino acids, in length. Examples of antigens presented in various
immune responses are described in more detail below and are
generally known in the art (Engelhard, Curr. Opin. Immun., 6:13-23
(1994)).
[0125] Suitable antigens are known in the art and are available
from commercial government and scientific sources. Criteria for
identifying and selecting effective antigenic peptides (e.g.,
minimal peptide sequences capable of eliciting an immune response)
can be found in the art. For example, Apostolopoulos, et al. (Curr.
Opin. Mol. Ther., 2:29-36 (2000)), discusses the strategy for
identifying minimal antigenic peptide sequences based on an
understanding of the three-dimensional structure of an
antigen-presenting molecule and its interaction with both an
antigenic peptide and T-cell receptor. Shastri, (Curr. Opin.
Immunol., 8:271-7 (1996)), disclose how to distinguish rare
peptides that serve to activate T cells from the thousands peptides
normally bound to MHC molecules.
[0126] The antigen can be derived from any source including, but
not limited to, a virus, bacterium, parasite, plant, protozoan,
fungus, tissue or transformed cell such as a cancer or leukemic
cell. The antigens may be purified or partially purified
polypeptides derived from tumors or viral or bacterial sources. The
antigens can be recombinant polypeptides produced by expressing DNA
encoding the polypeptide antigen in a heterologous expression
system. The antigens can be DNA encoding all or part of an
antigenic polypeptide. The DNA may be in the form of vector DNA
such as plasmid DNA.
[0127] Antigens may be provided as single antigens or may be
provided in combination. Antigens may also be provided as complex
mixtures of polypeptides or nucleic acids.
[0128] a. Viral Antigens
[0129] A viral antigen can be isolated from any virus including,
but not limited to, a virus from any of the following viral
families: Arenaviridae, Arterivirus, Astroviridae, Baculoviridae,
Badnavirus, Barnaviridae, Birnaviridae, Bromoviridae, Bunyaviridae,
Caliciviridae, Capillovirus, Carlavirus, Caulimovirus,
Circoviridae, Closterovirus, Comoviridae, Coronaviridae (e.g.,
Coronavirus, such as severe acute respiratory syndrome (SARS)
virus), Corticoviridae, Cystoviridae, Deltavirus, Dianthovirus,
Enamovirus, Filoviridae (e.g., Marburg virus and Ebola virus (e.g.,
Zaire, Reston, Ivory Coast, or Sudan strain)), Flaviviridae, (e.g.,
Hepatitis C virus, Dengue virus 1, Dengue virus 2, Dengue virus 3,
and Dengue virus 4), Hepadnaviridae, Herpesviridae (e.g., Human
herpesvirus 1, 3, 4, 5, and 6, and Cytomegalovirus), Hypoviridae,
Iridoviridae, Leviviridae, Lipothrixviridae, Microviridae,
Orthomyxoviridae (e.g., Influenzavirus A and B and C),
Papovaviridae, Paramyxoviridae (e.g., measles, mumps, and human
respiratory syncytial virus), Parvoviridae, Picornaviridae (e.g.,
poliovirus, rhinovirus, hepatovirus, and aphthovirus), Poxyiridae
(e.g., vaccinia and smallpox virus), Reoviridae (e.g., rotavirus),
Retroviridae (e.g., lentivirus, such as human immunodeficiency
virus (HIV) I and HIV 2), Rhabdoviridae (for example, rabies virus,
measles virus, respiratory syncytial virus, etc.), Togaviridae (for
example, rubella virus, dengue virus, etc.), and Totiviridae.
Suitable viral antigens also include all or part of Dengue protein
M, Dengue protein E, Dengue D1NS1, Dengue D1NS2, and Dengue
D1NS3.
[0130] Viral antigens may be derived from a particular strain such
as a papilloma virus, a herpes virus, i.e. herpes simplex 1 and 2;
a hepatitis virus, for example, hepatitis A virus (HAV), hepatitis
B virus (HBV), hepatitis C virus (HCV), the delta hepatitis D virus
(HDV), hepatitis E virus (HEV) and hepatitis G virus (HGV), the
tick-borne encephalitis viruses; parainfluenza, varicella-zoster,
cytomeglavirus, Epstein-Barr, rotavirus, rhinovirus, adenovirus,
coxsackieviruses, equine encephalitis, Japanese encephalitis,
yellow fever, Rift Valley fever, and lymphocytic
choriomeningitis.
[0131] b. Bacterial Antigens
[0132] Bacterial antigens can originate from any bacteria
including, but not limited to, Actinomyces, Anabaena, Bacillus,
Bacteroides, Bdellovibrio, Bordetella, Borrelia, Campylobacter,
Caulobacter, Chlamydia, Chlorobium, Chromatium, Clostridium,
Corynebacterium, Cytophaga, Deinococcus, Escherichia, Francisella,
Halobacterium, Heliobacter, Haemophilus, Hemophilus influenza type
B (HIB), Hyphomicrobium, Legionella, Leptspirosis, Listeria,
Meningococcus A, B and C, Methanobacterium, Micrococcus,
Myobacterium, Mycoplasma, Myxococcus, Neisseria, Nitrobacter,
Oscillatoria, Prochloron, Proteus, Pseudomonas, Phodospirillum,
Rickettsia, Salmonella, Shigella, Spirillum, Spirochaeta,
Staphylococcus, Streptococcus, Streptomyces, Sulfolobus,
Thermoplasma, Thiobacillus, and Treponema, Vibrio, and
Yersinia.
[0133] c. Parasite Antigens
[0134] Parasite antigens can be obtained from parasites such as,
but not limited to, an antigen derived from Cryptococcus
neoformans, Histoplasma capsulatum, Candida albicans, Candida
tropicalis, Nocardia asteroides, Rickettsia ricketsii, Rickettsia
typhi, Mycoplasma pneumoniae, Chlamydial psittaci, Chlamydial
trachomatis, Plasmodium falciparum, Trypanosoma brucei, Entamoeba
histolytica, Toxoplasma gondii, Trichomonas vaginalis and
Schistosoma mansoni. These include Sporozoan antigens, Plasmodian
antigens, such as all or part of a Cireumsporozoite protein, a
Sporozoite surface protein, a liver stage antigen, an apical
membrane associated protein, or a Merozoite surface protein.
[0135] d. Allergens and Environmental Antigens
[0136] The antigen can be an allergen or environmental antigen,
such as, but not limited to, an antigen derived from naturally
occurring allergens such as pollen allergens (tree-, herb, weed-,
and grass pollen allergens), insect allergens (inhalant, saliva and
venom allergens), animal hair and dandruff allergens, and food
allergens. Important pollen allergens from trees, grasses and herbs
originate from the taxonomic orders of Fagales, Oleales, Pinales
and platanaceae including La. birch (Betula), alder (Alnus), hazel
(Corylus), hornbeam (Carpinus) and olive (Olea), cedar (Cryptomeria
and Juniperus), Plane tree (Platanus), the order of Poales
including i.e. grasses of the genera Lolium, Phleum, Poa, Cynodon,
Dactylis, Holcus, Phalaris, Secale, and Sorghum, the orders of
Asterales and Urticales including i.a. herbs of the genera
Ambrosia, Artemisia, and Parietaria. Other allergen antigens that
may be used include allergens from house dust mites of the genus
Dermatophagoides and Euroglyphus, storage mite e.g Lepidoglyphys,
Glycyphagus and Tyrophagus, those from cockroaches, midges and
fleas e.g. Blatella, Periplaneta, Chironomus and Ctenocepphalides,
those from mammals such as cat, dog and horse, birds, venom
allergens including such originating from stinging or biting
insects such as those from the taxonomic order of Hymenoptera
including bees (superfamily Apidae), wasps (superfamily Vespidea),
and ants (superfamily Formicoidae). Still other allergen antigens
that may be used include inhalation allergens from fungi such as
from the genera Alternaria and Cladosporium.
[0137] e. Tumor Antigens
[0138] The antigen can be a tumor antigen, including a
tumor-associated or tumor-specific antigen, such as, but not
limited to, alpha-actinin-4, Bcr-Abl fusion protein, Casp-8,
beta-catenin, cdc27, cdk4, cdkn2a, coa-1, dek-can fusion protein,
EF2, ETV6-AML1 fusion protein, LDLR-fucosyltransferaseAS fusion
protein, HLA-A2, HLA-A11, hsp70-2, KIAAO205, Mart2, Mum-1, 2, and
3, neo-PAP, myosin class I, OS-9, pml-RAR.alpha. fusion protein,
PTPRK, K-ras, N-ras, Triosephosphate isomeras, Bage-1, Gage 3, 4,
5, 6, 7, GnTV, Herv-K-mel, Lage-1, Mage-A1, 2, 3, 4, 6, 10, 12,
Mage-C2, NA-88, NY-Eso-1/Lage-2, SP17, SSX-2, and TRP2-Int2, MelanA
(MART-I), gp100 (Pmel 17), tyrosinase, TRP-1, TRP-2, MAGE-1,
MAGE-3, BAGE, GAGE-I, GAGE-2, p15(58), CEA, RAGE, NY-ESO (LAGE),
SCP-1, Hom/Mel-40, PRAME, p53, H-Ras, HER-2/neu, BCR-ABL, E2A-PRL,
H4-RET, IGH-IGK, MYL-RAR, Epstein Barr virus antigens, EBNA, human
papillomavirus (HPV) antigens E6 and E7, TSP-180, MAGE-4, MAGE-5,
MAGE-6, p185erbB2, p180erbB-3, c-met, nm-23H1, PSA, TAG-72-4, CA
19-9, CA 72-4, CAM 17.1, NuMa, K-ras, .beta.-Catenin, CDK4, Mum-1,
p16, TAGE, PSMA, PSCA, CT7, telomerase, 43-9F, 5T4, 791Tgp72,
.alpha.-fetoprotein, 13HCG, BCA225, BTAA, CA 125, CA 15-3 (CA
27.29\BCAA), CA 195, CA 242, CA-50, CAM43, CD68\KP1, CO-029, FGF-5,
G250, Ga733 (EpCAM), HTgp-175, M344, MA-50, MG7-Ag, MOV18, NB\170K,
NY-CO-1, RCAS1, SDCCAG16, TA-90 (Mac-2 binding protein\cyclophilin
C-associated protein), TAAL6, TAG72, TLP, and TPS.
[0139] f. Self Antigens or Autoantigens
[0140] The antigen may also be a self antigen or an autoantigen.
Antigens may be antigens of any autoimmune or inflammatory disease
or disorder including, but not limited to, diabetes mellitus,
arthritis (including rheumatoid arthritis, juvenile rheumatoid
arthritis, osteoarthritis, psoriatic arthritis), multiple
sclerosis, myasthenia gravis, systemic lupus erythematosis,
autoimmune thyroiditis, dermatitis (including atopic dermatitis and
eczematous dermatitis), psoriasis, Sjogren's Syndrome, including
keratoconjunctivitis sicca secondary to Sjogren's Syndrome,
alopecia greata, allergic responses due to arthropod bite
reactions, Crohn's disease, ulcer, iritis, conjunctivitis,
keratoconjunctivitis, ulcerative colitis, asthma, allergic asthma,
cutaneous lupus erythematosus, scleroderma, vaginitis, proctitis,
drug eruptions, leprosy reversal reactions, erythema nodosum
leprosum, autoimmune uveitis, allergic encephalomyelitis, acute
necrotizing hemorrhagic encephalopathy, idiopathic bilateral
progressive sensorineural hearing loss, aplastic anemia, pure red
cell anemia, idiopathic thrombocytopenia, polychondritis, Wegener's
granulomatosis, chronic active hepatitis, Stevens-Johnson syndrome,
idiopathic sprue, lichen planus, Crohn's disease, Graves
opthalmopathy, sarcoidosis, primary biliary cirrhosis, uveitis
posterior, and interstitial lung fibrosis.
[0141] Preferred autoantigens of the present invention include, but
are not limited to, at least a portion of a thyroid-stimulating
hormone receptor, pancreatic P cell antigens, epidermal cadherin,
acetyl choline receptor, platelet antigens, nucleic acids, nucleic
acid protein complexes, myelin protein, thyroid antigens, joint
antigens, antigens of the nervous system, salivary gland proteins,
skin antigens, kidney antigens, heart antigens, lung antigens, eye
antigens, erythrocyte antigens, liver antigens and stomach
antigens.
[0142] Examples of antigens involved in autoimmune disease include
glutamic acid decarboxylase 65 (GAD 65), native DNA, myelin basic
protein, myelin proteolipid protein, acetylcholine receptor
components, thyroglobulin, and the thyroid stimulating hormone
(TSH) receptor.
[0143] Examples of antigens involved in graft rejection include
antigenic components of the graft to be transplanted into the graft
recipient such as heart, lung, liver, pancreas, kidney, and neural
graft components.
[0144] b. Polyclonal T Cell Receptor Activators
[0145] In another embodiment, the aAPCs described herein contain
polyclonal T cell receptor activators that activate T cells in the
absence of specific antigens. Suitable polyclonal T cell activators
include the mitogenic lectins concanavalin-A (ConA),
phytohemagglutinin (PHA) and pokeweed mitogen (PWM).
[0146] Other suitable polyclonal T cell activators include
antibodies that crosslink the T cell receptor/CD3 complex.
Exemplary antibodies that crosslink the T cell receptor include the
HIT3a, UCHT1 and OKT3 monoclonal antibodies.
[0147] D. Co-Stimulatory and T Cell Adhesion Molecules
[0148] In addition to ligation of the T cell receptor, activation
and proliferation of lymphocytes are regulated by both positive and
negative signals from costimulatory molecules. The most extensively
characterized T cell costimulatory pathway is B7-CD28, in which
B7-1 (CD80) and B7-2 (CD86) each can engage the stimulatory CD28
receptor and the inhibitory CTLA-4 (CD152) receptor. In conjunction
with signaling through the T cell receptor, CD28 ligation increases
antigen-specific proliferation of T cells, enhances production of
cytokines, stimulates differentiation and effector function, and
promotes survival of T cells (Lenshow, et al., Annu. Rev. Immunol.,
14:233-258 (1996); Chambers and Allison, Curr. Opin. Immunol.,
9:396-404 (1997); and Rathmell and Thompson, Annu. Rev. Immunol.,
17:781-828 (1999)).
[0149] The polymeric aAPCs described herein contain at least one
co-stimulatory molecule. Exemplary co-stimulatory molecules, also
referred to as "co-stimulators", include, but are not limited to,
CD7, B7-1 (CD80), B7-2 (CD86), PD-L1, PD-L2, 4-1BBL, OX40L,
inducible co-stimulatory ligand (ICOS-L), intercellular adhesion
molecule (ICAM), CD2, CD5, CD9, CD30L, CD40, CD70, CD83, HLA-G,
MICA, MICB, HVEM, lymphotoxin beta receptor, 3/TR6, ILT3, ILT4,
HVEM, an agonist or antibody that binds Toll ligand receptor and a
ligand that specifically binds with B7-H3. Other exemplary
co-stimulatory molecules that can be used include antibodies that
specifically bind with a co-stimulatory molecule present on a T
cell, such as, but not limited to, CD27, CD28, 4-IBB, OX40, CD30,
CD40, PD-1, ICOS, lymphocyte function-associated antigen-1 (LFA-1),
CD2, CD7, LIGHT, NKG2C, B7-H3, and a ligand that specifically binds
with CD83. Other suitable costimulatory molecules include, but are
not limited to, costimulatory variants and fragments of the natural
ligands described above.
[0150] Adhesion molecules may be included for the purpose of
enhancing the binding association between the aAPCs and T cells.
Suitable adhesion molecules include, but are not limited to, LFA-1,
CD49d/29(VLA-4), CD11a/18, CD54(ICAM-1), and CD106(VCAM) and
antibodies to their ligands. Other suitable adhesion molecules
include antibodies to selectins L, E, and P.
[0151] E. Cytokines and Growth Factors
[0152] Cytokines, the largest class of immunoregulatory molecules,
are secreted by activated APCs after T cell encounters and impact
expansion, survival, effector function, and memory of stimulated T
cells. Typically, cytokines are added to cultures exogenously and
administered systemically to patients following re-infusion of T
cells, however, such systemic administration can be associated with
acute toxicity as in the case of IL-2 in clinical trials (Fyfe, et
al., J. Clin. Oncol., 13(3):688-96 (1995)). While exogenous
addition of cytokines is a simple strategy to augment signaling, it
has been discovered that paracrine release of cytokines from
polymeric aAPCs represents a more efficacious strategy. The
examples below demonstrate that paracrine release of cytokines from
polymeric aAPCs mimics the paracrine release cytokines from natural
APCs and enhances T cell activation and proliferation with a lesser
concentration of cytokine relative to exogenous administration. The
examples also demonstrate that paracrine release of IL-2 from aAPCs
results in preferential expansion of CD8.sup.+ T cells, as compared
to CD4.sup.+ T cells.
[0153] The aAPCs disclosed herein contain cytokines encapsulated in
or incorporated into the polymeric microparticles. Suitable
cytokines include, but are not limited to, hematopoietic growth
factors, interleukins, interferons, immunoglobulin superfamily
molecules, tumor necrosis factor family molecules and chemokines.
Preferred cytokines include, but are not limited to, granulocyte
macrophage colony stimulating factor (GM-CSF), tumor necrosis
factor alpha (TNF.alpha.), tumor necrosis factor beta (TNF.beta.),
macrophage colony stimulating factor (M-CSF), interleukin-1 (IL-1),
interleukin-2 (IL-2), interleukin-4 (IL-4), interleukin-5 (IL-5),
interleukin-6 (IL-6), interleukin-10 (IL-10), interleukin-12
(IL-12), interleukin-15 (IL-15), interleukin-21 (IL-21), interferon
alpha (IFN.alpha.), interferon beta (IFN.beta.), interferon gamma
(IFN.gamma.), and IGIF, and variants and fragments thereof.
[0154] Suitable chemokines include, but are not limited to, an
alpha-chemokine or a beta-chemokine, including, but not limited to,
a C5a, interleukin-8 (IL-8), monocyte chemotactic protein 1alpha
(MIP1.alpha.), monocyte chemotactic protein 1 beta (MIP1.beta.),
monocyte chemoattractant protein 1 (MCP-1), monocyte
chemoattractant protein 3 (MCP-3), platelet activating factor
(PAFR), N-formyl-methionyl-leucyl-[.sup.3H]phenylalanine (FMLPR),
leukotriene B.sub.4, gastrin releasing peptide (GRP), RANTES,
eotaxin, lymphotactin, IP10, I-309, ENA78, GCP-2, NAP-2 and
MGSA/gro, and variants and fragments thereof.
[0155] It is known that polypeptides can be instable during
preparation, storage and release from polymeric microparticles.
Cytokines that are encapsulated in or incorporated into the
polymeric microparticles may be first stabilized by complexing or
mixing with preservation agents. Suitable preservation agents
include, but are not limited to, trehalose, mannitol, PEG 400, PEG
2000, PEG 3350, albumins, phosphatidyl-choline, gelatin, tweens and
pluronics.
[0156] F. Contrast Agents and Other Markers
[0157] Optionally, modular polymeric aAPCs may further include
agents useful for determining the location of administered
particles. Agents useful for this purpose include fluorescent tags,
radionuclides and contrast agents.
[0158] Suitable imaging agents include, but are not limited to,
fluorescent molecules such as those described by Molecular Probes
(Handbook of fluorescent probes and research products), such as
Rhodamine, fluorescein, Texas red, Acridine Orange, Alexa Fluor
(various), Allophycocyanin, 7-aminoactinomycin D, BOBO-1, BODIPY
(various), Calcien, Calcium Crimson, Calcium green, Calcium Orange,
6-carboxyrhodamine 6G, Cascade blue, Cascade yellow, DAPI, DiA,
DiD, Dil, DiO, DiR, ELF 97, Eosin, ER Tracker Blue-White, EthD-1,
Ethidium bromide, Fluo-3, Fluo4, FM1-43, FM4-64, Fura-2, Fura Red,
Hoechst 33258, Hoechst 33342, 7-hydroxy-4-methylcoumarin, Indo-1,
JC-1, JC-9, JOE dye, Lissamine rhodamine B, Lucifer Yellow CH,
LysoSensor Blue DND-167, LysoSensor Green, LysoSensor Yellow/Blu,
Lysotracker Green FM, Magnesium Green, Marina Blue, Mitotracker
Green FM, Mitotracker Orange CMTMRos, MitoTracker Red CMXRos,
Monobromobimane, NBD amines, NeruoTrace 500/525 green, Nile red,
Oregon Green, Pacific Blue. POP-1, Propidium iodide, Rhodamine 110,
Rhodamine Red, R-Phycoerythrin, Resorfin, RH414, Rhod-2, Rhodamine
Green, Rhodamine 123, ROX dye, Sodium Green, SYTO blue (various),
SYTO green (Various), SYTO orange (various), SYTOX blue, SYTOX
green, SYTOX orange, Tetramethylrhodamine B, TOT-1, TOT-3,
X-rhod-1, YOYO-1, YOYO-3.
[0159] Additionally radionuclides can be used as imaging agents.
Suitable radionuclides include, but are not limited to radioactive
species of Fe(III), Fe(II), Cu(II), Mg(II), Ca(II), and Zn(II)
Indium, Gallium and Technetium. Other suitable contrast agents
include metal ions generally used for chelation in paramagnetic
T1-type MIR contrast agents, and include di- and tri-valent cations
such as copper, chromium, iron, gadolinium, manganese, erbium,
europium, dysprosium and holmium. Metal ions that can be chelated
and used for radionuclide imaging, include, but are not limited to
metals such as gallium, germanium, cobalt, calcium, indium,
iridium, rubidium, yttrium, ruthenium, yttrium, technetium,
rhenium, platinum, thallium and samarium. Additionally metal ions
known to be useful in neutron-capture radiation therapy include
boron and other metals with large nuclear cross-sections. Also
suitable are metal ions useful in ultrasound contrast, and X-ray
contrast compositions.
[0160] Examples of other suitable contrast agents include gases or
gas emitting compounds, which are radioopaque.
[0161] G. Pharmaceutically Acceptable Excipients
[0162] The compositions may be administered in combination with a
physiologically or pharmaceutically acceptable carrier, excipient,
or stabilizer. The term "pharmaceutically acceptable" means a
non-toxic material that does not interfere with the effectiveness
of the biological activity of the active ingredients. The term
"pharmaceutically-acceptable carrier" means one or more compatible
solid or liquid fillers, dilutants or encapsulating substances
which are suitable for administration to a human or other
vertebrate animal. The term "carrier" refers to an organic or
inorganic ingredient, natural or synthetic, with which the active
ingredient is combined to facilitate the application.
[0163] Pharmaceutical compositions may be formulated in a
conventional manner using one or more physiologically acceptable
carriers including excipients and auxiliaries which facilitate
processing of the active compounds into preparations which can be
used pharmaceutically. Proper formulation is dependent upon the
route of administration chosen. In the preferred embodiment,
administration is by injection. Typical formulations for injection
include a carrier such as sterile saline or a phosphate buffered
saline. Viscosity modifying agents and preservatives are also
frequently added.
[0164] Optional pharmaceutically acceptable excipients especially
for enteral, topical and mucosal administration, include, but are
not limited to, diluents, binders, lubricants, disintegrants,
colorants, stabilizers, and surfactants. Diluents, also referred to
as "fillers," are typically necessary to increase the bulk of a
solid dosage form so that a practical size is provided for
compression of tablets or formation of beads and granules. Suitable
diluents include, but are not limited to, dicalcium phosphate
dihydrate, calcium sulfate, lactose, sucrose, mannitol, sorbitol,
cellulose, microcrystalline cellulose, kaolin, sodium chloride, dry
starch, hydrolyzed starches, pregelatinized starch, silicone
dioxide, titanium oxide, magnesium aluminum silicate and powdered
sugar.
[0165] Binders are used to impart cohesive qualities to a solid
dosage formulation, and thus ensure that a tablet or bead or
granule remains intact after the formation of the dosage forms.
Suitable binder materials include, but are not limited to, starch,
pregelatinized starch, gelatin, sugars (including sucrose, glucose,
dextrose, lactose and sorbitol), polyethylene glycol, waxes,
natural and synthetic gums such as acacia, tragacanth, sodium
alginate, cellulose, including hydroxypropylmethylcellulose,
hydroxypropylcellulose, ethylcellulose, and veegum, and synthetic
polymers such as acrylic acid and methacrylic acid copolymers,
methacrylic acid copolymers, methyl methacrylate copolymers,
aminoalkyl methacrylate copolymers, polyacrylic
acid/polymethacrylic acid and polyvinylpyrrolidone.
[0166] Lubricants are used to facilitate tablet manufacture.
Examples of suitable lubricants include, but are not limited to,
magnesium stearate, calcium stearate, stearic acid, glycerol
behenate, polyethylene glycol, talc, and mineral oil.
[0167] Disintegrants are used to facilitate dosage form
disintegration or "breakup" after administration, and generally
include, but are not limited to, starch, sodium starch glycolate,
sodium carboxymethyl starch, sodium carboxymethylcellulose,
hydroxypropyl cellulose, pregelatinized starch, clays, cellulose,
alginine, gums or cross linked polymers, such as cross-linked PVP
(POLYPLASDONE.RTM. XL from GAF Chemical Corp).
[0168] Stabilizers are used to inhibit or retard decomposition
reactions which include, by way of example, oxidative
reactions.
[0169] Surfactants may be anionic, cationic, amphoteric or nonionic
surface active agents. Suitable anionic surfactants include, but
are not limited to, those containing carboxylate, sulfonate and
sulfate ions. Examples of anionic surfactants include sodium,
potassium, ammonium of long chain alkyl sulfonates and alkyl aryl
sulfonates such as sodium dodecylbenzene sulfonate; dialkyl sodium
sulfosuccinates, such as sodium dodecylbenzene sulfonate; dialkyl
sodium sulfosuccinates, such as sodium
bis-(2-ethylthioxyl)-sulfosuccinate; and alkyl sulfates such as
sodium lauryl sulfate. Cationic surfactants include, but are not
limited to, quaternary ammonium compounds such as benzalkonium
chloride, benzethonium chloride, cetrimonium bromide, stearyl
dimethylbenzyl ammonium chloride, polyoxyethylene and coconut
amine. Examples of nonionic surfactants include ethylene glycol
monostearate, propylene glycol myristate, glyceryl monostearate,
glyceryl stearate, polyglyceryl-4-oleate, sorbitan acylate, sucrose
acylate, PEG-150 laurate, PEG-400 monolaurate, polyoxyethylene
monolaurate, polysorbates, polyoxyethylene octylphenylether,
PEG-1000 cetyl ether, polyoxyethylene tridecyl ether, polypropylene
glycol butyl ether, Poloxamer.RTM. 401, stearoyl
monoisopropanolamide, and polyoxyethylene hydrogenated tallow
amide. Examples of amphoteric surfactants include sodium
N-dodecyl-b-alanine, sodium N-lauryl-b-iminodipropionate,
myristoamphoacetate, lauryl betaine and lauryl sulfobetaine.
[0170] If desired, the particles may also contain minor amount of
nontoxic auxiliary substances such as wetting or emulsifying
agents, dyes, pH buffering agents, or preservatives.
[0171] The particles may be complexed with other agents. The
pharmaceutical compositions may take the form of, for example,
tablets or capsules prepared by conventional means with
pharmaceutically acceptable excipients such as binding agents
(e.g., acacia, methylcellulose, sodium carboxymethylcellulose,
polyvinylpyrrolidone (Povidone), hydroxypropyl methylcellulose,
sucrose, starch, and ethylcellulose); fillers (e.g., corn starch,
gelatin, lactose, acacia, sucrose, microcrystalline cellulose,
kaolin, mannitol, dicalcium phosphate, calcium carbonate, sodium
chloride, or alginic acid); lubricants (e.g. magnesium stearates,
stearic acid, silicone fluid, talc, waxes, oils, and colloidal
silica); and disintegrators (e.g. micro-crystalline cellulose, corn
starch, sodium starch glycolate and alginic acid. If water-soluble,
such formulated complex then may be formulated in an appropriate
buffer, for example, phosphate buffered saline or other
physiologically compatible solutions. Alternatively, if the
resulting complex has poor solubility in aqueous solvents, then it
may be formulated with a non-ionic surfactant such as TWEEN.TM., or
polyethylene glycol. Thus, the compounds and their physiologically
acceptable solvates may be formulated for administration.
[0172] Liquid formulations for oral administration prepared in
water or other aqueous vehicles may contain various suspending
agents such as methylcellulose, alginates, tragacanth, pectin,
kelgin, carrageenan, acacia, polyvinylpyrrolidone, and polyvinyl
alcohol. The liquid formulations may also include solutions,
emulsions, syrups and elixirs containing, together with the active
compound(s), wetting agents, sweeteners, and coloring and flavoring
agents. Various liquid and powder formulations can be prepared by
conventional methods for inhalation by the patient.
[0173] The particles may be further coated. Suitable coating
materials include, but are not limited to, cellulose polymers such
as cellulose acetate phthalate, hydroxypropyl cellulose,
hydroxypropyl methylcellulose, hydroxypropyl methylcellulose
phthalate and hydroxypropyl methylcellulose acetate succinate;
polyvinyl acetate phthalate, acrylic acid polymers and copolymers,
and methacrylic resins that are commercially available under the
trade name EUDRAGIT.RTM. (Rohm Pharma, Darmstadt, Germany), zein,
shellac, and polysaccharides. Additionally, the coating material
may contain conventional carriers such as plasticizers, pigments,
colorants, glidants, stabilization agents, pore formers and
surfactants.
III. Methods of Manufacture
[0174] A. Methods of Making Cytokine-Encapsulated
Microparticles
[0175] Many different processes can be used to form the nano- or
microparticles. If the process does not produce particles having a
homogenous size range, then the particles can be separated using
standard techniques such as sieving to produce a population of
particles having the desired size range.
[0176] i. Solvent Evaporation
[0177] Methods for forming nanoparticles using solvent evaporation
techniques are described in E. Mathiowitz, et al., J. Scanning
Microscopy, 4:329 (1990); Beck, et al., Fertil. Steril., 31:545
(1979); Beck, et al., Am. J. Obstet. Gynecol., 135(3) (1979);
Benita, et al., J. Pharm. Sci., 73:1721 (1984); and U.S. Pat. No.
3,960,757 to Morishita, et al. The polymer is dissolved in a
volatile organic solvent, such as methylene chloride. A substance
to be incorporated optionally is added to the solution, and the
mixture is suspended in an aqueous solution that contains a surface
active agent such as poly(vinyl alcohol). Substances which can be
incorporated in the nanoparticles include, but are not limited to,
cytokines, chemokines, interleukins and growth factors. The
resulting emulsion is stirred until most of the organic solvent
evaporated, leaving solid nano- and microparticles.
[0178] In a preferred embodiment, cytokine-loaded, spherical PLGA
microparticles with a mean diameter of 1-20 .mu.m and protein
loadings of up to 40% are produced by a modified version of this
technique. This method is useful for relatively stable polymers
like polyesters and polystyrene. However, labile polymers, such as
polyanhydrides, may degrade during the fabrication process due to
the presence of water. For these polymers, some of the following
methods performed in completely anhydrous organic solvents are more
useful.
[0179] ii. Hot Melt Microencapsulation
[0180] Microparticles can be formed from polymers such as
polyesters and polyanhydrides using hot melt microencapsulation
methods as described in Mathiowitz, et al., Reactive Polymers,
6:275 (1987). In this method, the use of polymers with molecular
weights between 3-75,000 daltons is preferred. In this method, the
polymer first is melted and then mixed with the solid particles of
a substance to be incorporated that have been sieved to less than
50 microns. The mixture is suspended in a non-miscible solvent
(like silicon oil), and, with continuous stirring, heated to above
the melting point of the polymer, for example, 5.degree. C. Once
the emulsion is stabilized, it is cooled until the polymer
particles solidify. The resulting microparticles are washed by
decanting with petroleum ether to give a free-flowing powder.
Microparticles with sizes between one to 1000 microns are obtained
with this method.
[0181] iii. Solvent Extraction
[0182] This technique is primarily designed for polyanhydrides and
is described, for example, in WO 93/21906 to Brown University
Research Foundation. In this method, the substance to be
incorporated is dispersed or dissolved in a solution of the
selected polymer in a volatile organic solvent, such as methylene
chloride. This mixture is suspended by stirring in an organic oil,
such as silicon oil, to form an emulsion. Microspheres that range
between 1-300 microns can be obtained by this procedure.
[0183] iv. Spray-Drying
[0184] Methods for forming microspheres using spray drying
techniques are described in U.S. Pat. No. 6,620,617, to Mathiowitz
et al. In this method, the polymer is dissolved in an organic
solvent such as methylene chloride or in water. A known amount of
an agent to be incorporated is suspended (insoluble agent) or
co-dissolved (soluble agent) in the polymer solution. The solution
or the dispersion then is spray-dried. Microspheres ranging between
0.1-10 microns are obtained.
[0185] v. Phase Inversion
[0186] Microparticles can be formed from polymers using a phase
inversion method wherein a polymer is dissolved in a "good"
solvent, fine particles of a substance to be incorporated, such as
a drug, are mixed or dissolved in the polymer solution, and the
mixture is poured into a strong non-solvent for the polymer, to
spontaneously produce, under favorable conditions, polymeric
microparticles, wherein the polymer is either coated with the
particles or the particles are dispersed in the polymer. The method
can be used to produce microparticles in a wide range of sizes,
including, for example, about 100 nanometers to about 10 microns.
Exemplary polymers which can be used include polyvinylphenol and
polylactic acid. Substances which can be incorporated include, for
example, imaging agents such as fluorescent dyes, or biologically
active molecules such as proteins or nucleic acids. In the process,
the polymer is dissolved in an organic solvent and then contacted
with a non-solvent, which causes phase inversion of the dissolved
polymer to form small spherical particles, with a narrow size
distribution optionally incorporating a cytokine or other
substance.
[0187] B. Methods of Attaching Coupling Agents to
Microparticles
[0188] Coupling agents may be conjugated to affinity tags prior to,
or after their association with polymeric microparticles. In a
preferred embodiment, the coupling agents are fatty acids and the
affinity tag is avidin/streptavidin. In a more preferred
embodiment, palmitic acid is conjugated to avidin. Avidin is
dissolved at a concentration of 5 mg/ml in 37.degree. C. prewarmed
2 ml solution of 2% deoxycholate in 1.times.PBS. To this solution,
a 10 fold molar excess of NHS-Palmitic acid is added and the
solution is stirred and sonicated in 37.degree. C. water bath
(Branson, 50 kHz freq.). The reaction is maintained at 37.degree.
C. for 24 hours after which excess palmitic acid is removed by
dialysis against a 0.15% deoxycholate-PBS buffer prewarmed to
37.degree. C. After three buffer changes, the avidin-palmitic acid
conjugate is verified by reverse phase HPLC on a Prevail C18 column
with a linear methanol gradient in 1.times.PBS as the mobile phase
and UV detection at 280 nm. This method is easily adapted to
conjugate avidin to any fatty acid of choice.
[0189] Avidin may be coupled to peptides and polymers by similar
techniques. The chemistry involved in the coupling reaction will
depend on the nature of available functional groups on the fatty
acid, peptide or polymer. Methods for conjugating avidin to fatty
acids, peptides and polymers are well known in the art. Methods for
conjugating other affinity tags such as biotin, epitope tags (HA,
FLAG, c-myc) and antibodies to fatty acids, peptides and polymers
are well known in the art.
[0190] In a preferred embodiment, coupling agents such as those
described above, including fatty acids, hydrophobic or aliphatic
peptides, and polymers, are conjugated onto the surface of
microparticles at the emulsion stage of microparticle preparation.
In a particularly preferred embodiment, the microparticles include
PLGA and the coupling agents include avidin-conjugated palmitic
acid. Dissolved. PLGA solution is added to a 4 ml solution of 2
parts avidin-palmitic acid, 2 parts 5% PVA. A 50:50 mixture of
protein-palmitic acid conjugates and 5% PVA has been found to yield
optimal surface coverage of avidin groups on nano- and microsized
particles.
[0191] C. Methods for Producing Polypeptides
[0192] Isolated polypeptides can be obtained by, for example,
chemical synthesis or by recombinant production in a host cell. To
recombinantly produce a costimulatory polypeptide, a nucleic acid
containing a nucleotide sequence encoding the polypeptide can be
used to transform, transduce, or transfect a bacterial or
eukaryotic host cell (e.g., an insect, yeast, or mammalian cell).
In general, nucleic acid constructs include a regulatory sequence
operably linked to a nucleotide sequence encoding a costimulatory
polypeptide. Regulatory sequences (also referred to herein as
expression control sequences) typically do not encode a gene
product, but instead affect the expression of the nucleic acid
sequences to which they are operably linked.
[0193] Useful prokaryotic and eukaryotic systems for expressing and
producing polypeptides are well know in the art include, for
example, Escherichia coli strains such as BL-21, and cultured
mammalian cells such as CHO cells.
[0194] In eukaryotic host cells, a number of viral-based expression
systems can be utilized to express polypeptides. Viral based
expression systems are well known in the art and include, but are
not limited to, baculoviral, SV40, retroviral, or vaccinia based
viral vectors.
[0195] Mammalian cell lines that stably express variant
costimulatory polypeptides can be produced using expression vectors
with appropriate control elements and a selectable marker. For
example, the eukaryotic expression vectors pCR3.1 (Invitrogen Life
Technologies) and p91023(B) (see Wong et al. (1985) Science
228:810-815) are suitable for expression of variant costimulatory
polypeptides in, for example, Chinese hamster ovary (CHO) cells,
COS-1 cells, human embryonic kidney 293 cells, NIH3T3 cells, BHK21
cells, MDCK cells, and human vascular endothelial cells (HUVEC).
Following introduction of an expression vector by electroporation,
lipofection, calcium phosphate, or calcium chloride
co-precipitation, DEAE dextran, or other suitable transfection
method, stable cell lines can be selected (e.g., by antibiotic
resistance to G418, kanamycin, or hygromycin). The transfected
cells can be cultured such that the polypeptide of interest is
expressed, and the polypeptide can be recovered from, for example,
the cell culture supernatant or from lysed cells. Alternatively,
polypeptides can be produced by (a) ligating amplified sequences
into a mammalian expression vector such as pcDNA3 (Invitrogen Life
Technologies), and (b) transcribing and translating in vitro using
wheat germ extract or rabbit reticulocyte lysate.
[0196] Polypeptides can be isolated using, for example,
chromatographic methods such as DEAE ion exchange, gel filtration,
and hydroxylapatite chromatography. For example, a polypeptide in a
cell culture supernatant or a cytoplasmic extract can be isolated
using a protein G column. In some embodiments, polypeptides can be
"engineered" to contain an amino acid sequence that allows the
polypeptides to be captured onto an affinity matrix. For example, a
tag such as c-myc, hemagglutinin, polyhistidine, or Flag.TM.
(Kodak) can be used to aid polypeptide purification. Such tags can
be inserted anywhere within the polypeptide, including at either
the carboxyl or amino terminus. Other fusions that can be useful
include enzymes that aid in the detection of the polypeptide, such
as alkaline phosphatase. Immunoaffinity chromatography also can be
used to purify polypeptides.
[0197] D. Methods for Producing Isolated Nucleic Acid Molecules
[0198] Isolated nucleic acid molecules can be produced by standard
techniques, including, without limitation, common molecular cloning
and chemical nucleic acid synthesis techniques. For example,
polymerase chain reaction (PCR) techniques can be used to obtain an
isolated nucleic acid encoding a variant costimulatory polypeptide.
PCR is a technique in which target nucleic acids are enzymatically
amplified. Typically, sequence information from the ends of the
region of interest or beyond can be employed to design
oligonucleotide primers that are identical in sequence to opposite
strands of the template to be amplified. PCR can be used to amplify
specific sequences from DNA as well as RNA, including sequences
from total genomic DNA or total cellular RNA. Primers typically are
14 to 40 nucleotides in length, but can range from 10 nucleotides
to hundreds of nucleotides in length. General PCR techniques are
described, for example in PCR Primer: A Laboratory Manual, ed. by
Dieffenbach and Dveksler, Cold Spring Harbor Laboratory Press,
1995. When using RNA as a source of template, reverse transcriptase
can be used to synthesize a complementary DNA (cDNA) strand. Ligase
chain reaction, strand displacement amplification, self-sustained
sequence replication or nucleic acid sequence-based amplification
also can be used to obtain isolated nucleic acids. See, for
example, Lewis (1992) Genetic Engineering News 12:1; Guatelli et
al. (1990) Proc. Natl. Acad. Sci. USA 87:1874-1878; and Weiss
(1991) Science 254:1292-1293.
[0199] Isolated nucleic acids can be chemically synthesized, either
as a single nucleic acid molecule or as a series of
oligonucleotides (e.g., using phosphoramidite technology for
automated DNA synthesis in the 3' to 5' direction). For example,
one or more pairs of long oligonucleotides (e.g., >100
nucleotides) can be synthesized that contain the desired sequence,
with each pair containing a short segment of complementarity (e.g.,
about 15 nucleotides) such that a duplex is formed when the
oligonucleotide pair is annealed. DNA polymerase can be used to
extend the oligonucleotides, resulting in a single, double-stranded
nucleic acid molecule per oligonucleotide pair, which then can be
ligated into a vector. Isolated nucleic acids can also obtained by
mutagenesis. Nucleic acids can be mutated using standard
techniques, including oligonucleotide-directed mutagenesis and/or
site-directed mutagenesis through PCR. See, Short Protocols in
Molecular Biology. Chapter 8, Green Publishing Associates and John
Wiley & Sons, edited by Ausubel et al, 1992. Examples of amino
acid positions that can be modified include those described
herein.
[0200] E. Methods of Attaching Functional Elements to Coupling
Agents
[0201] Functional elements can routinely be assembled onto coupling
agents incorporated onto the microparticle surface by conjugating
the functional elements to affinity tags which are complementary to
the affinity tags conjugated to the coupling agents. Especially
useful affinity tag pairs for use in coupling adaptor elements to
functional elements are biotin-avidin and biotin-streptavidin.
Affinity tag-conjugated functional elements are incubated with
microparticles pre-coated with adaptor elements conjugated to
complementary affinity tags under any appropriate buffer, salt and
detergent conditions. For example, typical incubations may be
performed at 4.degree. C. for 2-4 hours, 37.degree. C. for 20
minutes or room temperature for 1 hour. Incubations may be
performed in phosphate buffered saline or other buffer compositions
adjusted to a pH between 6.0 and 7.4. Incubation may occur with
gentle shaking, rocking or rotation. Microparticles may then be
washed with excess incubation buffer to remove unbound or
non-specifically bound functional elements.
[0202] Functional elements may also be conjugated directly to
adaptor elements in the absence of affinity tags, either prior to,
or after their association with polymeric microparticles. Methods
for conjugating functional elements such as peptides, polypeptides,
polymers and antibodies to adaptor elements such as fatty acids,
peptides and polymers are well known in the art. For example, fatty
acids such as palmitic acid may be conjugated to the C-terminus of
peptides, polypeptides and antibodies using a methodology similar
to that described above for conjugation of palmitic acid to
avidin.
IV. Methods of Use
[0203] The aAPCs are useful for activating T cells either in vivo,
for active immunotherapy applications, or ex vivo, for adoptive
immunotherapy applications. Activation of T cells by aAPCs
increases their proliferation, cytokine production,
differentiation, effector functions and/or survival. Methods for
measuring these are well known to those in the art. The T cells
activated by the aAPCs can be any cell which express the T cell
receptor, including .alpha./.beta. and .gamma./.delta. T cell
receptors. T-cells include all cells which express CD3, including
T-cell subsets which also express CD4 and CD8. T-cells include both
naive and memory cells and effector cells such as CTL. T-cells also
include regulatory cells such as Th1, Tc1, Th2, Tc2, Th3, Treg, and
Tr1 cells. T-cells also include NKT-cells and similar unique
classes of the T-cell lineage. In preferred embodiments the T cells
that are activated are CD8.sup.+ T cells. As demonstrated in the
examples below, the aAPCs disclosed herein preferentially activate
and expand CD8.sup.+ T cells when activated ex viva or in viva,
while many other aAPC platforms, both cellular and acellular,
preferentially expand CD4+ T cells (Kim, et al., Nat. Biotechnol.,
22:403-10 (2004); Oelke, et al., Trends Mol. Med., 11:412-20
(2005).
[0204] A. Subjects to be Treated
[0205] In general, the aAPCs described herein are useful for
treating a subject having or being predisposed to any disease or
disorder to which the subjects immune system mounts an immune
response. Treating a disease or disorder to which the subject's
immune system mounts an immune response may include inhibiting or
delaying the development of the disease or disorder or inhibiting
or reducing the symptoms of the disease or disorder. The
compositions are useful as prophylactic compositions, which confer
resistance in a subject to subsequent tumor development or exposure
to infectious agents. The compositions are also useful as
therapeutic compositions, which can be used to initiate or enhance
a subject's immune response to a pre-existing antigen, such as a
tumor antigen in a subject with cancer, or a viral antigen in a
subject infected with a virus.
[0206] The compositions are also useful to treat or prevent
diseases and disorders characterized by undesirable activation,
overactivation or inappropriate activation of the immune system,
such as occurs during allergic responses, autoimmune diseases and
disorders, graft rejection and graft-versus-host-disease. Methods
for using aAPCs for treatment of these conditions is described in
more detail below.
[0207] The ability of the aAPCs to elicit T-cell mediated immune
responses by activation and expansion of T cells makes these
compositions especially useful for eliciting a cell-mediated
response to a disease-related antigen in order to attack the
disease. Thus, in a preferred embodiment, the type of disease to be
treated or prevented is a malignant tumor or a chronic infectious
disease caused by a bacterium, virus, protozoan, helminth, or other
microbial pathogen that enters intracellularly and is attacked,
i.e., by the cytotoxic T lymphocytes.
[0208] The desired outcome of a prophylactic, therapeutic or
de-sensitized immune response may vary according to the disease,
according to principles well known in the art. For example, an
immune response against an infectious agent may completely prevent
colonization and replication of an infectious agent, affecting
"sterile immunity" and the absence of any disease symptoms.
However, treatment against infectious agents with aAPCs may be
considered effective if it reduces the number, severity or duration
of symptoms; if it reduces the number of individuals in a
population with symptoms; or reduces the transmission of an
infectious agent. Similarly, immune responses against cancer,
allergens or infectious agents may completely treat a disease, may
alleviate symptoms, or may be one facet in an overall therapeutic
intervention against a disease. For example, the stimulation of an
immune response against a cancer may be coupled with surgical,
chemotherapeutic, radiologic, hormonal and other immunologic
approaches in order to affect treatment.
[0209] i. Subjects Infected with or Exposed to Infectious
Agents
[0210] In some instances, the subject can be treated
prophylactically, such as when there may be a risk of developing
disease from an infectious agent. Infectious agents include
bacteria, viruses and parasites. An individual traveling to or
living in an area of endemic infectious disease may be considered
to be at risk and a candidate for prophylactic vaccination against
the particular infectious agent. Preventative treatment can be
applied to any number of diseases where there is a known
relationship between the particular disease and a particular risk
factor, such as geographical location or work environment.
[0211] iI. Subjects with or a Risk of Developing Malignant
Tumors
[0212] In a mature animal, a balance usually is maintained between
cell renewal and cell death in most organs and tissues. The various
types of mature cells in the body have a given life span; as these
cells die, new cells are generated by the proliferation and
differentiation of various types of stem cells. Under normal
circumstances, the production of new cells is so regulated that the
numbers of any particular type of cell remain constant.
Occasionally, though, cells arise that are no longer responsive to
normal growth-control mechanisms. These cells give rise to clones
of cells that can expand to a considerable size, producing a tumor
or neoplasm. A tumor that is not capable of indefinite growth and
does not invade the healthy surrounding tissue extensively is
benign. A tumor that continues to grow and becomes progressively
invasive is malignant. The term cancer refers specifically to a
malignant tumor. In addition to uncontrolled growth, malignant
tumors exhibit metastasis. In this process, small clusters of
cancerous cells dislodge from a tumor, invade the blood or
lymphatic vessels, and are carried to other tissues, where they
continue to proliferate. In this way a primary tumor at one site
can give rise to a secondary tumor at another site. The
compositions and method described herein may be useful for treating
subjects having malignant tumors. Treating a subject having a
malignant tumor includes delaying or inhibiting the growth of a
tumor in a subject, reducing the growth or size of the tumor,
inhibiting or reducing metastasis of the tumor, and inhibiting or
reducing symptoms associated with tumor development or growth. For
instance, the examples below demonstrate that the aAPCs disclosed
herein are effective in significantly delaying the growth of tumors
in vivo.
[0213] Malignant tumors which may be treated are classified herein
according to the embryonic origin of the tissue from which the
tumor is derived. Carcinomas are tumors arising from endodermal or
ectodermal tissues such as skin or the epithelial lining of
internal organs and glands. A melanoma is a type of carcinoma of
the skin for which this invention is particularly useful. Sarcomas,
which arise less frequently, are derived from mesodermal connective
tissues such as bone, fat, and cartilage. The leukemias and
lymphomas are malignant tumors of hematopoietic cells of the bone
marrow. Leukemias proliferate as single cells, whereas lymphomas
tend to grow as tumor masses. Malignant tumors may show up at
numerous organs or tissues of the body to establish a cancer.
[0214] The types of cancer that can be treated in with the provided
compositions and methods include, but are not limited to, the
following: bladder, brain, breast, cervical, colo-rectal,
esophageal, kidney, liver, lung, nasopharangeal, pancreatic,
prostate, skin, stomach, uterine, and the like. Administration is
not limited to the treatment of an existing tumor or infectious
disease but can also be used to prevent or lower the risk of
developing such diseases in an individual, i.e., for prophylactic
use. Potential candidates for prophylactic vaccination include
individuals with a high risk of developing cancer, i.e., with a
personal or familial history of certain types of cancer.
[0215] iii. Immunosuppressed Conditions
[0216] AAPCs can be used for treatment of disease conditions
characterized by immunosuppression, including, but not limited to,
AIDS or AIDS-related complex, idiopathic immunosuppression, drug
induced immunosuppression, other virally or environmentally-induced
conditions, and certain congenital immune deficiencies. AAPCs can
also be employed to increase immune function that has been impaired
by the use of radiotherapy of immunosuppressive drugs (e.g.,
certain chemotherapeutic agents), and therefore can be particularly
useful when used in conjunction with such drugs or
radiotherapy.
[0217] iv. Subjects Exposed to Allergens
[0218] The compositions and methods disclosed herein are useful to
treat and/or preventing allergic reactions, such as allergic
reactions which lead to anaphylaxis. Allergic reactions may be
characterized by the T.sub.H2 responses against an antigen leading
to the presence of IgE antibodies. Stimulation of T.sub.H1 immune
responses and the production of IgG antibodies may alleviate
allergic disease. Thus, the disclosed vaccine compositions may lead
to the production of antibodies that prevent and/or attenuate
allergic reactions in subjects exposed to allergens. These can be
used to enhance blocking or tolerance inducing reactions.
[0219] v. Subjects with or at Risk of Developing Autoimmune
Diseases or Disorders
[0220] The compositions and methods are useful for the treatment or
prevention of autoimmune diseases and disorders. Exemplary
autoimmune diseases include vasculitis, Wegener's granulomatosis,
Addison's disease, alopecia, ankylosing spondylitis,
antiphospholipid syndrome, Behcet's disease, celiac disease,
chronic fatigue syndrome, Crohn's disease, ulcerative colitis, type
I diabetes, fibromyalgia, autoimmune gastritis, Goodpasture
syndrome, Graves' disease, idiopathic thrombocytopenic purpura
(ITP), lupus, Meniere's multiple sclerosis, myasthenia gravis,
pemphigus vulgaris, primary biliary cirrhosis, psoriasis,
rheumatoid arthritis, rheumatic fever, sarcoidosis, scleroderma,
vitiligo, vasculitis, small vessel vasculitis, hepatitis, primary
biliary cirrhosis, rheumatoid arthritis, Chrohn's disease,
ulcerative colitis, sarcoidosis, scleroderma, graft versus host
disease (acute and chronic), aplastic anemia, and cyclic
neutropenia.
[0221] vI. Subjects Undergoing or at Risk of Graft Rejection or
Graft-Versus-Host Disease
[0222] The compositions and methods are useful for the treatment or
prevention of graft rejection or graft versus host disease. The
methods and compositions can be used in the prevention or treatment
of any type of allograft rejection or graft versus host disease for
any type of graft, including a xenograft. The allograft can be an
organ transplant, such as, but not limited to, a heart, kidney,
liver, lung or pancreas. Alternatively, the allograft can be a
tissue transplant, such as, but not limited to, heart valve,
endothelial, cornea, eye lens or bone marrow tissue transplant. In
yet other embodiments, the allograft can be a skin graft.
[0223] B. Adoptive immunotherapy
[0224] A source of T cells is obtained from a subject to be treated
for use in adoptive immunotherapy in an organism in which an immune
response can be elicited, e.g., mammals. Examples of subjects
include humans, dogs, cats, mice, rats, and transgenic species
thereof, although humans are preferred. T cells can be obtained
from a number of sources, including peripheral blood leukocytes,
bone marrow, lymph node tissue, spleen tissue, and tumors. In a
preferred embodiment, peripheral blood leukocytes are obtained from
an individual by leukopheresis. To isolate T cells from peripheral
blood leukocytes, it may be necessary to lyse the red blood cells
and separate peripheral blood leukocytes from monocytes by, for
example, centrifugation through, e.g., a PERCOLL.TM. gradient.
[0225] A specific subpopulation of T cells, such as CD4.sup.+ or
CD8.sup.+ T cells, can be further isolated by positive or negative
selection techniques. For example, negative selection of a T cell
population can be accomplished with a combination of antibodies
directed to surface markers unique to the cells negatively
selected. One suitable technique includes cell sorting via negative
magnetic immunoadherence, which utilizes a cocktail of monoclonal
antibodies directed to cell surface markers present on the cells
negatively selected. For example, to isolate CD4.sup.+ cells, a
monoclonal antibody cocktail typically includes antibodies to CD14,
CD20, CD11b, CD16, HLA-DR, and CD8. The process of negative
selection results in an essentially homogenous population of the
desired T cell population.
[0226] AAPCs are customized according to the subject and the
condition or disease to be treated. In one embodiment, the aAPCs
contain at least one polyclonal T cell receptor activator, such as
an anti-T cell receptor antibody. Polyclonal T cell activation can
be useful because it can expand a T cell population more quickly
than antigen-specific methods. The expanded polyclonal T cells can
then be sorted to select for T cells with a specificity for the
epitopes of interest. In another embodiment, the aAPCs contain MHC
class I or MHC class II molecules bound to antigens of interest for
antigen-specific T cell activation. The MHC polypeptides used in
the aAPCs are preferably selected to match the MHC alleles
expressed by the subject to be treated. The antigen is selected
based on the condition or disease to be treated or prevented. The
antigen may be derived from the subject to be treated.
[0227] The selected T cells are then contacted in appropriate
medium with the aAPCs. AAPCs are used in amounts effective to cause
activation and proliferation of T cells. The T cells are contacted
with the aAPCs for periods of time necessary for expansion of the T
cells. It may be advantageous to maintain long-term culture of a
population of T cells following the initial activation and
stimulation, by separating the T cells from the stimulus after a
period of about 12 to about 14 days. In certain embodiments, it may
be desirable to separate the T cells from the stimulus after a
period of about 2, 3, 4, 5, 6, 7, 8, 9, 10, or 11 days. In certain
embodiments, it may be desirable to separate the T cells from the
stimulus after a period of less than one day, such as after about
an hour, or 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17,
18, 19, 20, 21, 22, or 23 hours. The rate of T cell proliferation
is monitored periodically (e.g., daily) by, for example, examining
the size or measuring the volume of the T cells, such as with a
Coulter Counter. In this regard, a resting T cell has a mean
diameter of about 6.8 microns, and upon initial activation and
stimulation, in the presence of the stimulating ligand, the T cell
mean diameter will increase to over 12 microns by day 4 and begin
to decrease by about day 6. The T cells may be stimulated through
multiple rounds of activation by the aAPCs. For example, when the
mean T cell diameter decreases to approximately 8 microns, the T
cells may be reactivated and re-stimulated to induce further
proliferation of the T cells. Alternatively, the rate of T cell
proliferation and time for T cell re-stimulation can be monitored
by assaying for the presence of cell surface molecules, such as,
CD154, CD54, CD25, CD137, CD134, which are induced on activated T
cells.
[0228] Following activation and expansion of the T cells, they are
administered to the subject in amounts effective to induce an
immune response. The T cells may be administered separately from,
or in combination with, the aAPCs. The immune response induced in
the animal by administering the compositions may include cellular
immune responses mediated by CD8.sup.+ T cells, capable of killing
tumor and infected cells, and CD4.sup.+ T cell responses. Humoral
immune responses, mediated primarily by B cells that produce
antibodies following activation by CD4.sup.+ T cells, may also be
induced. In a preferred embodiment, the immune response is mediated
by cytolytic CD8.sup.+ T cells. A variety of techniques which are
well known in the art may be used for analyzing the type of immune
responses induced by the compositions and methods disclosed herein
(Coligan et al., Current Protocols in Immunology, John Wiley &
Sons Inc. (1994)).
[0229] i. Adoptive Immunotherapy of Autoimmune Diseases and
Disorders, Allergic Reactions, Graft Rejection and
Graft-Versus-Host-Disease
[0230] Adoptive immunotherapy may also be used to treat or prevent
conditions associated with undesirable activation, over-activation
or inappropriate or aberrant activation of an immune response, as
occurs in conditions including autoimmune disorders and diseases,
allergic reactions, graft rejection and graft-versus-host disease.
In one embodiment, undesirable or aberrant antigen-specific immune
responses are treated or prevented by adoptive immunotherapy using
"regulatory" T cells (Tregs) activated by the compositions and
methods disclosed herein.
[0231] Immunological self-tolerance is critical for the prevention
of autoimmunity and maintenance of immune homeostasis. The ability
of the immune system to discriminate between self and non-self is
controlled by mechanisms of central and peripheral tolerance.
Central tolerance involves deletion of self-reactive T lymphocytes
in the thymus at an early stage of development (Rocha, et al.,
Science, 251:1225-1228 (1991); Kisielow, et al., Nature,
333:742-746 (1988)). Several mechanisms of peripheral tolerance
have been described, including T cell anergy and ignorance
(Schwartz, Science, 248:1349-1356 (1990); Miller, et al., Immunol.
Rev., 133:131-150 (1993)). Studies have provided firm evidence for
the existence of a unique CD4.sup.+CD25.sup.+ population of
professional regulatory/suppressor T cells that actively and
dominantly prevent both the activation as well as the effector
function of autoreactive T cells that have escaped other mechanisms
of tolerance (Sakaguchi, et al., J. Immunol., 155:1151-1164 (1995);
Takahashi, et al., Int. Immunol., 10:1969-1980 (1998); Itoh, et
al., J. Immunol., 162:5317-5326 (1999)). The elimination or
inactivation of these cells resulted in severe autoimmune disease,
and was also found to enhance immune responses to alloantigens and
even tumors (Sakaguchi, et al., J. Immunol., 155:1151-1164 (1995);
Itoh, et al., J. Immunol., 162:5317-5326 (1999); Shimizu, et al.,
J. Immunol., 163:5211-5218 (1999)). Autoantigen-specific regulatory
T (Treg) cells actively regulate autoimmunity and induce long term
tolerance and have application as a strategy for inducing
long-lived tolerance.
[0232] T cells are obtained from the subject to be treated as
described above, and a Treg enriched cell population is obtained by
negative and or positive selection. An autoantigen-specific
regulatory T (Treg) cell enriched composition is one in which the
percentage of autoantigen-specific Treg cells is higher than the
percentage of autoantigen-specific Treg cells in the originally
obtained population of cells. In particular embodiments, at least
75%, 85%, 90%, 95%, or 98% of said cells of the composition are
autoantigen-specific regulatory T cells. To maximize efficacy, the
subpopulation is enriched to at least 90%, preferably at least 95%,
and more preferably at least 98% Treg cells, preferably
CD4.sup.+CD25.sup.+CD62L.sup.+ Treg cells. Positive selection may
be combined with negative selection against cells comprising
surface makers specific to non-Treg cell types, such as depletion
of CD8, CD11b, CD16, CD19, CD36 and CD56-bearing cells.
[0233] The Treg cells are activated in a polyclonal or
antigen-specific manner ex vivo using the compositions, as
described above, expanded, and administered to the subject to be
treated. In another embodiment, a population of T cells not
enriched for Treg cells is activated and expanded, and the Treg
cells are selected from the expanded T cell population using
appropriate positive and/or negative selection.
[0234] Adoptive immunotherapy using Treg cells can be used for
prophylactic and therapeutic applications. In prophylactic
applications, Treg cells are administered in amounts effective to
eliminate or reduce the risk or delay the outset of conditions
associated with undesirable activation, over-activation or
inappropriate or aberrant activation of an immune response,
including physiological, biochemical, histologic and/or behavioral
symptoms of the disorder, its complications and intermediate
pathological phenotypes presenting during development of the
disease or disorder. In therapeutic applications, the compositions
and methods disclosed herein are administered to a patient
suspected of, or already suffering from such a condition associated
with undesirable activation, over-activation or inappropriate or
aberrant activation of an immune response to treat, at least
partially, the symptoms of the disease (physiological, biochemical,
histologic and/or behavioral), including its complications and
intermediate pathological phenotypes in development of the disease
or disorder. An amount adequate to accomplish therapeutic or
prophylactic treatment is defined as a therapeutically- or
prophylactically-effective amount.
[0235] With respect to allograft rejection or graft versus host
disease, in a preferred embodiment, adoptive immunotherapy with
Treg cells is initiated prior to transplantation of the allograft.
In certain embodiments, the Treg cells can be administered to the
subject for a day, three days, a week, two weeks or a month prior
to a transplantation. In other embodiments, the Treg cells are
administered for a week, two weeks, three weeks, one month, two
months, three months or six months following a transplantation. In
a preferred embodiment, Treg cells are administered both before and
after a transplantation is carried out.
[0236] The outcome of the therapeutic and prophylactic methods
disclosed herein is to at least produce in a patient a healthful
benefit, which includes, but is not limited to, prolonging the
lifespan of a patient, delaying the onset of one or more symptoms
of the disorder, and/or alleviating a symptom of the disorder after
onset of a symptom of the disorder. For example, in the context of
allograft rejection, the therapeutic and prophylactic methods can
result in prolonging the lifespan of an allograft recipient,
prolonging the duration of allograft tolerance prior to rejection,
and/or alleviating a symptom associated with allograft
rejection.
[0237] In another embodiment, undesirable or aberrant
antigen-specific immune responses are treated or prevented by
adoptive immunotherapy by using the compositions to activate and
expand T cells specific for IgE or CD40L.
[0238] Immune responses to foreign, sometimes innocuous, substances
such as pollen, dust mites, food antigens and bee sting can result
in allergic diseases such as hay fever, asthma and systemic
anaphylaxis. Immune responses to self-antigens such as pancreatic
islet antigens and cartilage antigens can lead to diabetes and
arthritis, respectively. The hallmark of the allergic diseases is
activation of CD4.sup.+ T cells and high production of IgE by B
cells, whereas the salient feature of autoimmune diseases are
activation of CD4.sup.+ T cells and over production of inflammation
cytokines. Activated CD4.sup.+ T cells transiently express the self
antigen CD40L.
[0239] Cytotoxic T lymphocytes (CTLs) specific for antigenic
peptides derived from IgE molecule can be generated ex vivo using
the artificial antigen presenting cells and methods disclosed
herein presenting antigenic IgE peptides. These IgE specific CTLs
can be administered to a subject to lyse the target cells loaded
with IgE peptides and inhibit antigen specific IgE responses in
vivo. These IgE specific CTLs can also be used to prevent or treat
the development of lung inflammation and airway
hypersensitivity.
[0240] Similarly, cytotoxic T lymphocytes (CTLs) specific for
antigenic peptides derived from CD40L can be generated ex vivo
using the artificial antigen presenting cells and methods disclosed
herein presenting antigenic CD40L peptides. These CD40L specific
CTLs can be administered to a subject to lyse target activated
CD4.sup.+ cells in vivo. These CD40L specific CTLs can be used to
inhibit CD4-dependent antibody responses of all isotypes in
vivo.
[0241] C. Active Immunotherapy
[0242] The aAPCs disclosed herein can also be used for active
immunotherapy. For active immunotherapy, the aAPCs are administered
directly to the subject to be treated in the same manner as a
vaccine. In general, methods of administering polymeric
microparticles and vaccines are well known in the art. Any
acceptable method known to one of ordinary skill in the art may be
used to administer a formulation to the subject. The administration
may be localized (i.e., to a particular region, physiological
system, tissue, organ, or cell type) or systemic. AAPCs can be
administered by a number of routes including, but not limited to,
injection: intravenous, intraperitoneal, intramuscular, or
subcutaneous, to a mucosal surface (oral, sublingual or buccal,
nasal, rectal, vaginal, pulmonary), or transdermal. In some
embodiments, the injections can be given at multiple locations. The
aAPCs can also be administered directly to an appropriate lymphoid
tissue, such as the spleen, lymph nodes or mucosal-associated
lymphoid tissue.
[0243] Administration of the formulations may be accomplished by
any acceptable method which allows an effective amount of the aAPCs
to reach their target. The particular mode selected will depend
upon factors such as the particular formulation, the severity of
the state of the subject being treated, and the dosage required to
induce an effective immune response. As generally used herein, an
"effective amount" is that amount which is able to induce an immune
response in the treated subject. The actual effective amounts of
aAPCs can vary according to factors including the specific antigen
or combination thereof being utilized, the density and/or nature of
the associated co-stimulatory molecules, the release
characteristics of the encapsulated cytokines, the particular
composition formulated, the mode of administration, and the age,
weight, condition of the subject being treated, as well as the
route of administration and the disease or disorder.
[0244] Unless defined otherwise, all technical and scientific terms
used herein have the same meanings as commonly understood by one of
skill in the art to which the disclosed invention belongs.
Publications cited herein and the materials for which they are
cited are specifically incorporated by reference.
EXAMPLES
[0245] The present invention may be further understood by reference
to the following non-limiting examples.
Example 1
Fabrication of aAPCs
[0246] Materials and Methods:
[0247] Fabrication of aAPCs:
[0248] Poly(lactide-co-glycolide) (PLGA) 50/50 with an average
molecular weight of 80 kDa was obtained from Durect Corporation,
Cupertino, Calif. Microparticles were fabricated using a single
emulsion oil-in-water technique, while nanoparticles were created
using a double emulsion water-in-oil-in-water technique (Jain,
Biomaterials, 21(23):2475-90 (2000)). Both were surface modified
with avidin-palmitate conjugate as described previously (Fahmy, et
al., Biomaterials, 26(28):5727-36 (2005)). Particles were
lyophilized and stored at -20.degree. C. until use.
[0249] Characterization of aAPCs:
[0250] Particles were imaged using scanning electron microscopy.
Images were analyzed with NIH Image) to determine the size
distribution of particle diameters by counting at least 150
particles per sample. For loaded IL-2 aAPCs, a controlled release
profile was obtained in PBS at 37.degree. C. ELISA analysis was
performed to measure rhIL-2 levels (BD Biosciences, San Jose,
Calif.).
[0251] Ligand Coupling:
[0252] Biotinylated anti-mouse CD3.epsilon. (BD Biosciences, San
Jose, Calif.) or biotinylated peptide-loaded MHC-K.sup.b-Ig dimers
(obtained as a generous gift from Jonathan Schneck, Johns Hopkins
University) (Schneck, et al., Curr. Prot. Immunol., John Wiley
& Sons, Inc., pp. 17.12.11-17.12.17 (2000)) and anti-mouse CD28
(BD Biosciences, San Jose, Calif.) were added at 10 .mu.g/mL to a
10 mg/mL solution of PLGA particles in PBS and rotated at room
temperature for 20 minutes. Particles were washed with PBS+1% FBS
and resuspended in complete RPMI-10. Anti-CD28, when present, was
added at a 1:1 molar ratio to anti-CD3 or MHC-K.sup.b-Ig.
[0253] Results:
[0254] Both nanoparticles and microparticles were fabricated using
identical formulations. Particles were created using single
emulsion (microparticles) and double emulsion (micro- and
nanoparticles) techniques previously described (Jain, Biomaterials,
21:2475-90 (2000)) and were surface modified with avidin Fahmy, et
al., Biomaterials, 26:5727-5736 (2005)). Scanning electron
microscopy revealed particles with average diameters of 8.0 .mu.m
and 130 nm for micro- and nanoparticles, respectively (FIGS. 1A and
1B). Particles were qualitatively visualized with T cells, and
stable interactions were observed. The biocompatibility of
untargeted aAPCs (particles without attached biotinylated ligands)
was confirmed using a range of particle concentrations, and no
effect on proliferation was observed (FIG. 2).
Example 2
Antigen-Specific T Cell Stimulatory Effects of aAPCs
[0255] Materials and Methods:
[0256] Cell Lines and Primary Cells:
[0257] Animal studies were approved by the Institutional Animal
Care and Use Committee (IACUC) at Yale University. All animals were
routinely used at 6-8 weeks of age, were maintained under specific
pathogen-free conditions, and were routinely checked by the Yale
University Animal Resource Center. C57BL/6 (B6) mice were obtained
from Jackson Laboratories (Bar Harbor, Me.). OT-I TCR transgenic
breeder mice were a generous gift from Ruslan Medzhitov (Yale
University) and were bred heterozygous on a B6 background in our
animal facility. Phenotypes were screened using V-alpha2 and CD8a
antibodies (eBioscience, San Diego, Calif.). B3Z hybridoma cells
with TCR specific for SIINFEKL peptide (OVA.sub.257-264) were a
generous gift from Peter Cresswell (Yale University) and were
maintained in RPMI-1640 (Invitrogen, Carlsbad, Calif.) supplemented
with 10% FBS (Atlanta Biologicals, Lawrenceville, Ga.) and 2%
penicillin-streptomycin (Sigma Aldrich, St. Louis, Mo.). Primary
splenocytes were obtained from homogenized naive mouse spleens
after depletion of erythrocytes by hypotonic lysis (Acros Organics,
Geel, Belgium). Splenocytes were resuspended in complete RPMI-10,
consisting of RPMI-1640 supplemented with 10% FBS, 2 mM L-glutamine
(Invitrogen, Carlsbad, Calif.), 25 .mu.M .beta.-mercaptoethanol
(American Bioanalytical, Natick, Mass.), 2% penicillin-streptomycin
and 1% gentamicin (Sigma Aldrich, St. Louis, Mo.). B6 splenocytes
were used without further purification, while OT-I CD8.sup.+ T
cells were isolated by negative immunoselection (R&D Systems,
Minneapolis, Minn.).
[0258] T Cell Stimulation Studies:
[0259] aAPCs coated with antibody or MHC were titrated across rows
of a round-bottom 96-well plate (BD Biosciences, San Jose, Calif.)
in 100 .mu.l of media per well. Equal masses of micro- and
nanoparticles were used, beginning with a maximum concentration of
5 mg/mL. B6 splenocytes or OT-I CD8+ T cells were added to each
well at a final concentration of 5.times.10.sup.5 cells/mL (B6) or
1.times.10.sup.5 (OT-I). Non-biodegradable Dynal beads (4 .mu.m
diameter, Invitrogen, Carlsbad, Calif.) were used at a
concentration of beads equal to the PLGA microparticle
concentrations used (1.times.10.sup.5 microparticles/mg of
polymer). In all cases, the highest concentration of aAPCs or beads
corresponds to a 1:1 ratio of cells:particles, and the highest
antibody concentration is 5 .mu.g/mL. After incubation at
37.degree. C. for 60 hours, plates were centrifuged at 1,500 rpm
for 7 minutes in a table top centrifuge, and the supernatant was
removed for IFN-.gamma. ELISA analysis or mIL-2 ELISA. Cell pellets
were resuspended in media and analyzed for viability using Cell
Titer Blue (Promega, Madison, Wis.). For burst release studies,
aAPCs were allowed to release IL-2 in PBS at 37.degree. C. for 7
days prior to coupling to biotinylated anti-CD3 and anti-CD28 and
use in stimulation studies. For stability studies, assembled aAPCs
were incubated at 4.degree. C. for one week before use. Reported
values were obtained by using dilutions of supernatant that yielded
absorbance values within the linear portion of the standard
curve.
[0260] Data Fitting and Statistical Analysis:
[0261] Data fits were performed using GraphPad Prism 4.0.
Controlled release data were fit to a two-phase exponential
association model, and stimulation data were fit to a receptor
crosslinking model (MacGlashan, et al., J. Immunol., 135:4129-34
(1985)) where the equation of fit is given by:
Response = P 1 .delta. 1 + P 2 .delta. where .delta. = C max C ( C
max + C ) 2 ##EQU00001##
C is the independent variable, concentration of ligand, Cmaxis the
ligand concentration at which a maximal response is observed, and
P.sub.1 and P.sub.2 are parameters relating to the height and width
of the curve.
[0262] Results:
[0263] Micro- and nanoparticle aAPCs were coupled to biotinylated
MHC-Kb dimers loaded with the cognate OVA SIINFEKL peptide derived
from ovalbumin (OVA257-264) (Hogquist, et al., Cell, 76:17-27
(1994)) (SIINKb) or noncognate OVA SIYRYYGL peptide (SIYKb). At the
concentration of ligands used in these studies (1 .mu.g of
antibody/mg polymer or 5 .mu.g MHC/mg polymer), 90% of the protein
added was successfully bound to particles (FIG. 3). To assess the
optimal concentration of particles to be used with T cells, aAPCs
were titrated beginning at 5 mg/mL and incubated with purified
CD8.sup.+ T cells from OT-I mice, a class-I restricted T cell line
recognizing the SIINFEKL peptide presented within the context of
H-2 Kb. Activation was assessed by measuring IL-2 levels from cell
culture supernatant. Optimal stimulation was observed to occur at
an intermediate aAPC concentration, beyond which T cell IL-2
secretion declines (FIG. 4). Data were fit to a well-established
model that accounts for the biophysical aspects of this trend
(MacGlashan, et al., J. Immunol., 135(6):4129-34 (1985)), and model
fit parameters are given in Table 1. This model predicts that
activation of immune cells by multivalent ligands will exhibit
bell-shaped concentration dependence due to receptor aggregation on
the surface of the cells (MacGlashan, et al., J. Immunol.,
135(6):4129-34 (1985); Stone, et al., Biophys. J., 81(5):2547-57
(2001)). In this model, the decreased response at high ligand
concentrations is a result of less efficient aggregation between
ligands and receptors. Previous work has reported similar trends
showing symmetric, bell-shaped, non-saturating concentration
dependence when utilizing multivalent constructs for the
stimulation of T cells (van Rensen, et al., Pharm. Res.,
16(2):198-204 (1999); Stone, et al., Biophys. J., 81(5):2547-57
(2001); Fahmy, et al., Immunity, 14:135-43 (2001)).
TABLE-US-00001 TABLE 1 Summary of model fit parameters Treatment
C.sub.max (ng/ml) P.sub.1 P.sub.2 R2 Micorparticles 3607.0 114.5
-3.14 0.9646 Nanoparticles 5692.0 222.3 -0.08 0.9126 Soluble
27574.0 3060.0 34.38 0.9643 SIY 3146.0 17.3 -0.75 0.5735
nanocognate aAPC anti- 30.1 9.8 -3.95 0.0637 CD3 aAPC anti- 220.5
2359.0 -3.35 0.8909 CD3/28 aAPC anti- 140.8 3.30E+06 3.45 0.9059
CD3 aAPC anti- 343.4 1.20E+07 -2.31 0.9047 CD3/28 aAPC anti- 97.9
6.2 -3.48 0.4772 CD3 aAPC anti- 166.3 404.0 -2.11 0.9672 CD3/28
aAPC MHC 3607.0 114.5 -3.142 0.9646 aAPC 3474.0 193.1 -3.688 0.9738
MHC/anti- CD28 aAPC 52.0 6739.0 -2.059 0.9598 encapsulated IL-2
aAPC 158.1 912.0 -3.373 0.9380 exogenous IL-2 aAPC 107.9 412.5
-3.382 0.8487
[0264] Both micro- and nanoparticles exhibit bell-shaped curves,
but the stimulation maximum for microparticle aAPCs occurs at a
lower concentration of constructs than the maximal response from
nanoparticle aAPCs (FIG. 4). In addition to the shift in optimal
concentration, peak levels of IL-2 secretion were much higher in
response to microparticle aAPCs when compared to nanoparticle
aAPCs. These findings are supported by previous reports
demonstrating that micron-sized particles, which are close in size
to T cells, provide optimal T cell stimulation (Mescher, J.
Immunol., 149(7):2402-5 (1992)). From the peak of the curve in FIG.
4, it was deduced that for this aAPC system, a ratio of 1:8,
(particles:T cells) is optimal for stimulation.
Example 3
Effects of Co-Stimulatory Signals on the Effectiveness of aAPCs for
T Cell Stimulation
[0265] Materials and Methods:
[0266] Assessment of Expansion by Flow Cytometry:
[0267] CFSE-labeled B6 splenocytes or OT-I CD8 T cells
(2.times.10.sup.6 cells) were exposed to various concentrations of
soluble ligands (anti-CD3 for polyclonal stimulation and
.sup.SIINK.sup.b dimers for antigen-specific stimulation (anti-CD28
was present in both cases at a 1:1 molar ratio) or ligand coated
aAPCs in the presence or absence of rhIL-2 and trehalose.
Antibodies and rhIL-2 were added to achieve the indicated final
concentrations in 2 mL of media. aAPCs were added at 0.3 mg/mL
final concentration (40:1 cells:aAPCs). Dynal beads were used at a
3:1 ratio of beads:cells with concentrations of antibody equal to
aAPCs. All antibodies, aAPCs, rhIL-2, and trehalose were added at
the beginning of the experiment without restimulation during the
course of the study. Cell aliquots were obtained on day 4, and flow
cytometric analysis was performed using a Becton Dickenson FACScan
instrument (San Jose, Calif.) and FlowJo software (Tree Star, Inc.,
Ashland, Oreg.). Splenocytes were stained with a 1:200 dilution of
anti-CD8 PE and OT-I CD8.sup.+ T cells were stained with a 1:20
dilution of PE-labeled .sup.SIINK.sup.b tetramer (Beckman Coulter,
Fullerton, Calif.). Analysis of fluorescence was performed after
gating on the lymphocyte population in SSC vs. FSC plots, and,
where noted, the CD8.sup.+ subset. Staining for activation markers
was performed using anti-CD25, anti-CD44, and anti-CD69, all PE
labeled, and subset analysis employed anti-CD4 FITC and anti-CD8
PE. All antibodies were obtained from BD Biosciences, San Jose,
Calif. To measure absolute cellular expansion of splenocyte
cultures, cells were analyzed on a Multisizer3 (Beckman Coulter,
Fullerton, Calif.) at dilutions within the working range of the
instrument. Particle counts were independently measured and
subtracted from samples undergoing aAPC stimulation.
[0268] Fluorescence Microscopy:
[0269] B3Z cells were washed twice in PBS to remove serum proteins
before incubation with poly-Lysine-coated cover slips (BD
Biosciences, San Jose, Calif.). 1.times.10.sup.6 cells/mL were
added in serum-free RPMI 1640 at 37.degree. C. for 1 hour. The
cover slips were then blocked in RPMI-10 for 10 minutes at room
temperature. aAPCs with encapsulated Rhodamine B (Acros Organics,
Geel, Belgium) and attached anti-CD3 and anti-CD28 were added to
cover slips at 5 mg/mL in RPMI-10. Following a 1 hour incubation at
4.degree. C., cover slips were washed and fixed with 4%
paraformaldehyde (USB Corporation, Cleveland, Ohio) for 10 minutes
at room temperature. After fixing, the cells were permeabilized and
stained with phalloidin-FITC (Invitrogen, Carlsbad, Calif.) and
Vectashield with DAPI (Vector Laboratories, Burlingame, Calif.).
Slides were visualized using a Leica SP5 confocal microscope.
[0270] Results:
[0271] aAPCs were prepared with anti-CD28 and anti-CD3 for
polyclonal activation or .sup.SIINK.sup.b and anti-C28 for
antigen-specific activation. IL-2 and IFN-.gamma. secretion as well
as T cell proliferation were assessed to determine activation and
function of the cells. In the absence of co-stimulation, C57BL/6
(B6) T cells secreted minimal IL-2 and IFN-.gamma. and failed to
proliferate significantly (FIGS. 5A-5C). Addition of anti-CD28
induced robust cytokine secretion and enhanced proliferation.
Similarly, antigen-specific stimulation was increased by a
four-fold enhancement in IL-2 secretion on addition of
co-stimulatory molecules to the aAPC surface (FIG. 5D). These
results are consistent with previous studies that use polystyrene
latex microspheres for T cell stimulation (Deeths and Mescher, Eur.
J. Immunol., 27:598-608 (1997)) and show that incorporation of
co-stimulatory molecules on the particle surface improves T cell
expansion.
Example 4
Effects of Controlled Release of IL-2 from aAPCs on T Cell
Proliferation
[0272] Materials and Methods:
[0273] PLGA particles were fabricated generally as described above
in Example 1. For cytokine encapsulation, 100 .mu.g of rhIL-2
(obtained as a generous gift from Maria Parkhurst, NCI) was
lyophilized with a 10-fold excess by mass of trehalose (Sigma
Aldrich, St. Louis, Mo.) and incorporated as a solid during
fabrication (solid-in-oil-in-water single emulsion technique) or
added to 100 .mu.l of PBS (water-in-oil-in-water emulsion
technique) without trehalose.
[0274] All other materials and methods are as described above for
Examples 1-3 except where indicated.
[0275] Results:
[0276] The delivery of IL-2 increases the viability and
proliferative capacity of T cells (Janeway et al., Immunobiology:
The Immune System in Health and Disease, Garland Science
Publishing, New York, N.Y. (2005)). A distinct advantage of the
current platform is its ability to encapsulate and release, in a
sustained fashion, cytokines such as IL-2. Control over release of
the cytokine can be achieved by varying the particle preparation
conditions. To demonstrate these features, recombinant human IL-2
(rhIL-2) was encapsulated in microparticles using three methods: 1)
In phosphate buffered saline (PBS) using a double emulsion
water-in-oil-in-water (w/o/w) technique (low encapsulation with
burst release); 2) As a lyophilized solid using a single emulsion
solid-in-oil-in-water (s/o/w) technique (medium encapsulation with
burst); 3) By first stabilizing with trehalose, a known
preservation agent (van de Weert, et al., Pharmaceutical Res.,
8:713-720 (1159-1167)), then encapsulating using a single emulsion
s/o/w technique (high encapsulation and sustained release). In
control experiments trehalose had neither a stimulatory nor an
inhibitory effect on T cell activation. The kinetics of controlled
release of rhIL-2 from each type of microparticle aAPC in PBS are
shown in FIG. 6A. Controlled release curves were obtained from 10
mg of particles without attached biotinylated ligands. Attachment
of surface ligands does not affect release characteristics (Fahmy,
et al., Biomaterials, 26:5727-36 (2005)). The resulting biphasic
plots are typical of protein release during PLGA particle
degradation and are characterized by an initial burst release
followed by continual release of protein over time (Cohen, et al.,
Pharmaceutical Res., 8:713-20 (1991)). To examine the effect of
varying rhIL-2 loading on T cell stimulation, B6 splenocytes were
stimulated in a polyclonal manner by aAPCs fabricated with
different rhIL-2 loading (`loaded IL-2 aAPCs`) presenting anti-CD3
and anti-CD28. As expected, peak stimulation was observed with
lower aAPC concentrations encapsulating higher levels of rhIL-2
that is released in a gradual manner (FIG. 6B). Furthermore, this
mode of stimulation seemed to be more efficient than exogenous
addition of IL-2. To show this effect, IL-2 loaded aAPCs (s/o/w
trehalose-high) were compared to unloaded aAPCs in the presence and
absence of equal concentrations of exogenous, titrated rhIL-2 (5
ng/mL at highest concentration). While the addition of exogenous
rhIL-2 produced a moderate increase in IFN-.gamma. secretion,
paracrine delivery of rhIL-2 more than doubled this response (FIG.
6C). To determine whether this effect is due to the burst of
cytokine from the particle observed at early time points or
sustained release over time, particles were allowed to release
rhIL-2 at 37.degree. C. for 7 days, then washed and coupled to
antibodies prior to T cell stimulation. As shown in FIG. 6D, cells
exhibited only moderate decreases in IFN-.gamma. secretion when
stimulated by particles whose burst release was washed-off prior to
use. This supports the hypothesis that gradual release of cytokine
from the aAPC during the stimulation period has significant effects
on the magnitude of stimulation. Next the performance of this
system was compared to soluble antibodies and a commercially
available aAPC platform, 4 .mu.m Dynal beads (at equivalent
particle concentrations) loaded with anti-CD3 and anti-CD28, in the
presence of exogenous rhIL-2 (FIG. 6E). Soluble antibody and Dynal
beads induced lower IFN-.gamma. secretion than both loaded and
exogenous rhIL-2 aAPCs and appear to require higher concentrations
to achieve peak stimulation. Reported values for the optimal
stimulation of T cells with Dynal beads suggest that a 3:1 ratio of
beads to cells is ideal (Garlie, et al., J. Immunother., 22:336-45
(1999)). Here, optimal stimulation with loaded IL-2 aAPCs can be
achieved with a 1:64 (aAPC:T cell ratio) for polyclonal expansion
(FIGS. 6C and 6D).
Example 5
Effects of Paracrine Delivery of IL-2 Versus Exogeneous IL-2
Addition on T Cell Stimulation by aAPCs
[0277] Materials and Methods:
[0278] Materials and methods are generally as described above for
Examples 1-4 except where indicated.
[0279] Results:
[0280] To examine the effect of paracrine rhIL-2 delivery on T cell
expansion, CFSE dye-labeled 136 splenocytes were monitored during
polyclonal stimulation. Only loaded IL-2 aAPCs produced
near-complete division of T cells after 4 days of culture (FIG.
7A). Soluble antibodies and unloaded aAPCs were not as efficient in
facilitating T cell division even with a 10-fold increase in the
level of exogenous rhIL-2. In addition, significant improvements
were observed in the absolute number of cells expanded with IL-2
loaded aAPCs. After one week of culture without restimulation, 136
splenocytes showed a 45-fold expansion in absolute cell number
compared to other methods for stimulation (FIG. 7B). Polyclonal
expansion of T cells led to an increase in the proportion of
CD8.sup.+ T cells. Addition of exogenous rhIL-2 to cultures
containing unloaded aAPCs did not produce CD8.sup.+ CFSE.sup.LOW
populations equal to that of loaded IL-2 aAPCs. Increasing the
concentration of exogenous rhIL-2 improved stimulation, but
expansion remained less than cells treated with loaded IL-2 aAPCs.
Only increasing the concentrations of soluble antibody and rhIL-2
by an order of magnitude produced comparable effects with loaded
IL-2 aAPCs. Analogous results were observed with antigen-specific
stimulation, where the percentage of
.sup.SIINK.sup.b-tetramer-positive CFSE.sup.LOW cells was greatest
for loaded IL-2 aAPC stimulation.
Example 6
aAPCs Increase the Sensitivity of T Cells to IL-2 and Selectively
Expand CD8.sup.+ T Cells
[0281] Materials and Methods:
[0282] Materials and methods are generally as described above for
Examples 1-5 except where indicated.
[0283] Results:
[0284] CD25, the alpha chain of the IL-2 receptor, is an
established activation marker upregulated upon in vitro T cell
stimulation (Gattinoni, et al., Jour. Clin. Invest., 115:1616-26
(2005)). Expression of CD25 increased as a result of all
stimulation methods, but was further upregulated on cells exposed
to loaded IL-2 aAPCs (FIG. 5A). In addition, subset T cell analysis
revealed that loaded IL-2 aAPCs preferentially expand CD8.sup.+ T
cells with near 100% selectivity during polyclonal expansion (FIG.
8B). This is in contrast to other methods of stimulation
investigated in this work, including commercially available
magnetic beads. Unloaded aAPCs with and without rhIL-2 produced
near equal proportions of CD4.sup.+ and CD8.sup.+ T cells, while
soluble antibodies and Dynal beads (used at a 3:1 ratio of
beads:cells) in the presence or absence of exogenous rhIL-2
selectively expanded CD4.sup.+ T cells. These results are in
agreement with previous work demonstrating that some aAPC
platforms, both cellular and acellular, preferentially expand CD4+
T cells (Kim, et al., Nat. Biotechnol., 22:403-10 (2004); Oelke, et
al., Trends Mol. Med., 11:412-20 (2005)). T cells expanded with
loaded IL-2 aAPCs are functional and activated as inferred from the
upregulation of the activation markers CD25, CD44, and CD69.
Example 7
Induction of Effective Tumor Immunity by aAPCs in Mice
[0285] Materials and Methods:
[0286] Materials and methods are generally as described above for
Examples 1-5 except where indicated.
[0287] Treatment of Mice Injected with B16 Melanoma Tumor Cells
with aAPCs:
[0288] Mice were injected with B16 melanoma cells and tumors were
allowed to develop. Mice were treated with aAPCs fabricated with
anti-CD3 and anti-CD28 antibodies, as described above in Examples
1-3. Plain microparticles, lacking anti-CD3 and anti-CD28
antibodies were used as negative controls. Antibody-coated aAPCs
were either loaded with IL-2, or were not loaded. Each mouse was
injected subcutaneously on day 10 following injection of B16
melanoma cells with 2 mg of aAPCs in a total volume of 50 .mu.l.
Total tumor area of the B16 melanoma tumors was determined on days
10, 12, 14, 17, 19 and 24 following tumor cell injection.
[0289] Results:
[0290] To determine the ability of aAPCs to activate T cells in
vivo, and produce effective anti-tumor immunity, a
well-characterized mouse mouse cancer model, the B16 melanoma
model, was used. Mice were injected with B16 melanoma tumor cells,
and after allowing for the cells to develop small tumors, were
injected with plain microparticles, or anti-CD3 and anti-CD28
coated microparticles, either loaded with IL-2 or left
unloaded.
[0291] Administration of anti-CD3 and anti-CD28 coated
microparticles (aAPCs) caused a delay in tumor development in the
mice, as compared to plain microparticles, that was significantly
enhanced by encapsulation of IL-2 in the aAPCs (FIG. 9). The
significant delay in tumor growth was found to correlate with an
expansion of cytotoxic T lymphocytes and inhibition of regulatory T
cells in the vicinity of tumor growth.
* * * * *